Fbanks

I'm willing to write off that fusible link as just being old and corroded and past its time. My truck is more than 35 years old now, and that link was looking pretty bad and I doubt I'd ever replaced it before. I've been keeping an eye on the replacement, and so far so good there. That's a great tip and would have been the way I went had I known, but unfortunately, I had already ordered a replacement from RockAuto. I did check out the Maxima alternator, and they actually did have a no-name closeout for $38, which was about half price of what I paid for the AC/Delco 60A. On the plus side, after reading your post, I decided to take a look and see when the last time I replaced my alternator was (I keep pretty good records). In finding my records, I also found that the replacement was a lifetime warranty replacement from Autozone, originally bought in 1997, and replaced once in 2003. Autozone actually took my old unit back and gave me a new replacement, once the guys at the store figured out how to handle something that old. Surprisingly, they still had the warranty in their records (I did have an old receipt too, which wasn't needed), so I gotta give props to AZ on this one. I never even opened the one from RockAuto, so that one will go back. The AZ unit is just a 60A, but the last one was as well, and I got >20 years out of it, so hopefully this one holds up as well. I replaced the alternator this weekend, and so far, so good. Dash voltmeter showing 14V now when running, so all's looking good there. I even tested the front wiper and everything seemed to work just fine (other than the spray nozzles needing adjusting), including the delay switch as well. I did see the brown box by the wiper motor, but left well-enough alone for now. As I recall, this problem with the front wiper not turning off until I shut the truck down was intermittent, and would not happen every time. I tried it several times this weekend and couldn't get it to fail. I do recall replacing the multifunction switch on the steering column before, so it's possible I solved those old issues previously , and the undervoltage caused some similar reoccurence.

I'm adding on to this topic, since it might be related, and could be the reason for the original failure. The original failure started with a fusible link burning up, and the rear wiper started to run continuously after that. Rear wiper issue was resolved with replacement of the rear wiper amplifier unit. Flash forward to yesterday, and the truck was running fine, when a light mist started. I turned on the front windshield wiper, and noticed that the wiper seemed to run the same speed regardless of switch position, and the wiper also would not stop, even with the wiper switch in the off position. I don't drive the old truck that much anymore, but I do recall having this issue with the front wiper not stopping periodically in the past. Also, I recall the intermittent function rarely, if ever, worked anymore. I didn't worry too much about this, since I when I stopped the truck, the wiper would also stop, and would not resume when I started the truck again so long as the switch was in the off position. So back to yesterday- I shut the truck down when I could to kill the wiper, but when I went to restart, the truck would not turn over. I was luckily on a hill, so attempted to jump start her with the clutch. She did attempt to fire a couple times, but would not stay running. Took a look under the hood and failed to see anything obvious, but when I tried to start again, it turned over just enough to crank, and seemed to be running fine. Continued on my way until maybe 10 miles later going down the highway the truck just died, along with the instrument cluster and all power. You could hear the hazards clicking when I turned them on, but they were too weak to flash. Luckily, my brother was close by and was able to give me a jump, and the truck started fine. Checked some voltages and it appears the alternator has gone bad, and was unable to charge the battery. This behavoir continued as I made my way back home with the truck, having to get a couple of jumps along the way. I paid attention to the voltmeter on the truck on the way home, and noted that just after jumping, it would be at 12 volts and never got above that. At times, but not always, it would begin to drop and when it got down significantly below 12v, the truck would just die. Long story short-I believe the alternator is intermittently failing, but it made me wonder if this might not have been the cause of my fusible link and rear wiper amp failures earlier? I can't recall if the voltage regulator is built into the alternator or not, but perhaps it was putting out too much at some point and burnt the fusible link and the rear wiper amp? I'm planning to replace the alternator, which hopefully solves my problem, and also the issue of the front wiper speed not changing (i'm guessing it just didn't have enough juice to go faster). I don't expect it will solve my old problem with the front wiper, and I'll probably have to decide if that's worth fixing or not. I'm wondering if there's a front wiper amp, like the rear wiper amp? I'm thinking I recall briefly looking into this before, and hearing that the front wiper intermittent function was built into the wiper motor itself? I did inspect the fusible link after this episode, and it seems to be perfectly fine. So far as I can tell, there doesn't appear to be any electrical issues outside of the failing alternator. Any thoughts/advice on 1) the alternator being the cause of the earlier failures? And 2) potential causes of the front wiper failure to stop/intermittent wiper not working?

Final resolution- it was the rear wiper amp module that failed. I got a replacement unit and tested it, and all switch positions worked perfectly (interval, on, off, and wiper). The replacement came from a '95, so that confirms compatibility of unit from '95 model with that of '87 model Whether it was the fusible link failure that initially caused the rear wiper amp failure, or vice versa, we'll never know. Many thanks to Slartibartfast for the diagrams and all the guidance provided, as well as the replacement unit, which got me back fully functional again.

I decided to check the diodes with another meter, since my diode test on my meter seemed questionable. First, I should note that for all the readings I reported above, the forward- and reverse-bias notations should be reversed. The voltages listed were correct, at least according to that meter. With the 2nd meter, I got the following readings: Diode 1 (just in front of connector)- Forward-bias 0.575v Reverse bias 2.98v Diode 2 (beside connector)- Forward-bias 0.575v Reverse bias 1.4v Diode 3 (farthest from the connector)- Forward-bias 0.5v Reverse bias 0.58v Diode 4 (just behind diode #3, next to chip-looking thing)- Forward-bias 0.28v Reverse bias 0.28v I'm thinking to test these properly, I probably need to desolder/disconnect the cathode end of the diode? Diodes 1,2, and 3 appear to be the same, and have a 6.L marked on them, while diode #4 has a 6.8 marked on it

I do have a diode mode on my VM, so I took a look. If I'm right, there are 4 diodes on the board, 2 oriented at right angles to each other toward the front of the board, and 2 oriented at right angles to each other toward the connector side of the board. I'm not sure that the diode test is valid with them still being soldered on the board- only on one of these diodes (the one just in front of the connector) did I get the expected 0.7V in what I think was forward-biased condition. When I reverse-biased, I got 0.5V. For the diode beside the connector, I also got 0.5V when reverse-biased, but 2.0V when forward-biased. For the front-most diode toward the front of the board (the only one laying horizontal), I got 0.2V in both forward- and reverse-biased states, while I got 0.1V in both states for the other. I note that when in diode mode on my VM (Fluke 79), and the leads are totally open, the VM reads 2.4V. That doesn't seem normal

I did some more inspection and poking around on my board tonight, but failed to uncover anything. I think I'll have better success putting my effort into finding another amp unit, unless you want to part with yours? From your post above, I do believe that I should be ok with Pathfinder models from '87-'95.

I agree. I'm going to take a closer look at the board when I have some time to see if I can find anything defective that I can fix myself. I'm not real hopeful on that, but I figure it's worth a shot.

I went to test the amp module again according to your post above, but I immediately noticed something was off. I had left all the wires connected to the amp module, with the clips to the marine battery I was using for test purposes just clipped to the battery case, next to the terminals. But, I noticed the positive and negative terminals on the battery were in reverse order of where I thought they were. This means the previous testing I did when I went to replicate my first test, except now to measure across terminals 2 & 4, were invalid. I must have used the marine battery and put it back differently in between my original test, and the retest. I corrected my error, and tested again as I had previously. When I connected power to pin 5, I could hear the relay click, and I never heard it disengate. When reading across terminals 2 and 7, I got -2.3V, which is close to what I had gotten in my original tests (I did have different leads, so this seemed reasonable). But now, when I read across terminals 2 and 4, I got a -12.5V. It did not seem to matter whether I had pin 6 going to ground directly, or going to ground through one of my inline spark testers, or completely disconnected. The -12.5V was with the positive lead from the voltmeter going to pin 2, and the negative lead going to pin 4. Maybe the behavoir above with the disregard for pin 6 connection is consistent with what my rear wiper is doing (never cutting off)? Side note-I don't think those inline spark testers work as DC test lights, as I could not get mine to light up even going directly across the battery terminals.

When I tested before, I had pin 6 going directly to ground. I totally missed the screwdriver looking thing in the diagram, or took it for a banana plug jack or something. That's a good catch! I was also just using my voltmeter in place of the test light, across 2 and 4, or 2 and 7. I think I have a couple of inline spark testers around somewhere that I guess should work. I'll see if I can dig them out and give the test another try.

I wouldn't say I'm a great free-form troubleshooter. Give me a schematic and I can maybe figure a few things out, but I'm not sure if the traces on the board are even visible for me to follow. I'll take a closer look when I get a chance. I could try ohming it out, but that might not be that easy since I can't isolate the components easily, not to mention very tedious. I feel like I'm just close enough now to solving the problem that I hate to quit, but far enough away still to question if it's worth the effort. I might also try investigating some more junkyards, to see if I get lucky. I am concerned that if there are a bunch of different (and relevant) variations of this amp according to model year, it could prove to be a very difficult search, as I'd basically be restricted to '87-'88 pathfinders vs. '87-'94 I was initially a little confused by this, but when you're talking about going from a nine-pin to a four-pin switch, I think you mean the switch on the dash, right? And the pins on the amp connector (and the wires are the same? If so, do you think performing the fucntionality check in the service manual on your module using pins 2 and 4 would suffice as a compatability check?

Thx for that diagram- I tested the relays according to the diagram, and both relays acted just as expected. I had continuity from 1 to 4 when not energized, and when I applied 12V across terminals 2 and 5, I could hear the relays click, and I had continuity from 1 to 3. I also checked the other contact in both energized and non-energized states, and while not a complete open, I had something in the megaohms range on the open contact. I did not bother to desolder them from the board since I got the expected response. Just to be sure, I retested the amp again according to the service manual, and once again obtained the 0V across terminals 2 and 4.

Looking at the back of the board where the solder points are, and with the 3 terminals on the top, and assuming the layout is the same as that 3rd picture in the ebay posting above, I made an attempt to energize the relays. I assumed the coil would be across terminals 1 and 2, with terminal 1 being the top middle, slightly offset pin. Terminal 2 should be the pin to the right of it (looking at the underside of the board. When I put power across these terminals, I hear a buzzing (but no clicking, like I did from the test above) from one of the relays, but not the other. If I reverse the power/ground leads, and do the same, then I get a buzzing from the other relay, but not the first. I don't know why this would be, as the relays appear to be identical, and appear to be put in the exact same way. Anyhow, I have no idea what that means, as I made a couple assumptions- 1) I assumed the pinout matched that in the ebay posting, and 2) I assumed that the coil was across 1 and 2. Either of these could be bad assumptions.

Hey, thanks for digging that out. I retested the amplifier module again, this time with the voltmeter across terminals 2 and 4. Before connecting the power, the voltage was floating around 0.2v. When I connected the power, I could hear at least one relay clicking, and the voltmeter went to a solid 0v. Mostly there's capacitors and resistors on the board, along with a diode or 2. There are 2 larger boxes on the board with the following markings- Omron G8S-1117P-CUK. They look very similar to these relays on Ebay, that have the same part number, but without the "K" on the end (mine also have the number 24Z6DK underneath this part #, instead of 1180D6) https://www.ebay.com/itm/142203152250 Whereas these appear to have only 4 legs, mine have 5 solder points, so I'm assuming they would have 5 legs as well, though I have no idea why? I thought maybe they were just socketed in, and that I could just pull the body of the relay out, but that doesn't appear to be case, and it looks like the legs are soldered directly to the board.

I did manage to get it apart. There are small retaining tabs top and bottom, and if you get a small screwdriver between the plug and the casing, it pops out. The "tab" I thought Iwas pushing on was a retaining bracket for the plug pins. I don't think it's all that necessary, but I glued that back into place, and it should hold fine until I can get a replacement. Upon inspection, I did not see anything obvious on the board. All the solder points still looked nice and shiny with no obvious breaks, and no obvious burns anywhere on the board. I began to doubt my earlier test results, so I connected it back up again per the diagram in the service manual. When I connected the voltmeter across pins 2 & 7, I forgot that I still had the meter set to ohms. When I applied the power, a couple of the leads I was using for power/ground were quickly smoked, and the insulation burned back (kinda like my fusible link, though these were very thin alligator clip jumpers I had laying around). I quickly removed power, and set the meter to the DCV setting, and tested again. As before, I was still reading a negative ~3V. I plugged the amp back into the truck to test the function, and it still functioned just as it had before, so I guess no harm done with my mishap.

Thanks for checking! I'm pretty sure I tried to pop mine open, as I did see a tab there. When I pushed on the tab though, it broke off and fell inside, so I quit there rather than force the issue. I'll pull it out again and give it another try. I left the panels off for now so should be quick.

Many thanks, I appreciate it, and all the help you've provided!

I finished the tailgate switch- it was not effectively shorting when the door was open due to corrosion and bad contact. I cleaned it up real good, and bent the contact down a little until I got a good, consistent short, but still got an open when depressed. The mechanism itself seemed to be fine, and I could see it open the contact gap when pushed in, giving an open. It just wasn't getting a good short when in the released position. While I had it unplugged, I went ahead and tested the cargo lamp by jumpering the connector. Even with that, the only way I could get the cargo light to come on was by turning it to the "ON" position. I thought maybe it was the cargo lamp switch itself, but when i checked at the connector, I had 12v across Red/Grn and black, but 0v across red/grn and red/wht. So something else is off there.

I at least got the rear hatch switch working consistently now, so that's ready whenever I can get the rear wiper amplifier replaced. I started to do the rear tailgate switch as well, but i only got halfway through before it got dark. It seems a little more complicated, as it really won't come out from the outside the way the rear hatch switch does (the bolts will, but the latch assembly won't). And it seems in order to access it, you've got to remove the actuator panel as well in order to have any maneuvering room. It's only another 5 screws and another link or 2, so no biggie. I'll try to finish it tomorrow. I could definitely see some corrosion around the leads, but without being able to take it out yet, it was hard for me to see how the switch actually worked.

The part # on my unit says 28510-42G00, which looks like it's been superseded by B8510-42G85. However, I'm not showing that as available either. Anyone know a good source for really old Pathfinders? Just from Googling, it looks like this was also used on some later Terrano models as well, but I really don't even recall that model.

Hi again, thanks a lot for the info. I had some time today to take a further look. WRT to the cargo light, yes, there is a 3-position switch. My light stays off when in the middle position, but it turns on when I move it to the ON position. Off position also seems to work. I looked at the voltages coming in from the plug, and I believe the far left (Red/Grn) on the plug is +12V, while the middle pin is ground, and the far right pin (looking into the connector) is coming from the latch switch (red/white). When the switch is closed (rear door open), the red/white should be shorted to ground and allows the light to come on, if the switch at the lamp is in the right position. I guess my switch is stuck in the open position as I read +12v even with the rear door open , but I haven't had a chance to look at that yet. I did pull the rear wiper amplifier, and I tested it according to the diagram on EL-72. I'm pretty sure I connected everything properly, but I was reading a negative ~3 volts between pins 2 and 7 (with 7 being the ground). If I did everything correctly, then I guess my amp is bad? Now the question, where to find one?

Thanks for checking that out- yes, it is helpful. I can do without the hatch switch for now (easy enough for me to just remember not to pop the hatch with the wiper running), but if you know of a good source for that, I'd appreciate it. I have a hard time finding pathy's that old at local junkyards around. Even a part # would help (I don't think that's in the service manual you gave me?). I tried a search but don't seem to find a part resembling mine. Yes, that switch could have been out for a long time now, and I just never noticed it. I can't think of a time when I tried to run the rear wiper with the hatch opened. And from my tests the other day, I do recall I wasn't originally getting a good short out of it. I sprayed some electronic cleaner in there and it seemed to be working ok after that, so I thought it would be alright. I guess not, and it went bad for good this time. Maybe I can repair it once I remove the latch, but I'll have to take a look and see when I get there. Your mention of the cargo light also reminded me that I have to manually turn mine on, even when opening the whole tailgate. I would think that switch would be obvious, but I seem to recall looking for it some years ago, and not immediately finding it. If you can tell me where the tailgate switch is located, maybe I'll take a look at that too while I'm in there. I tried looking in the service manual, but didn't immediately find the physical location. It would be easier if I could do a search in that manual, and I thought Acrobat used to do an OCR recognition that would allow that, but I don't seem to have the option anymore. Back to the problem at hand- I'm looking at EL-72 which shows a test procedure for the amp. The text says "if the test lamp comes on when connected to terminal 6 and battery ground, the amp is good". But the diagram shows the test lamp connected between terminals 2 and 7. Terminal 6 they show as battery ground in that diagram, and terminal 7 is body ground according to the diagram on El-70. Do you think that's just a typo/mistake in the text description, and terminal 6 in the quote above should read terminal 2?

I had a little time before it got dark, and so checked out the relay/hatch switch. When I toggled the switch, I did not hear the relay clicking, and the wiper also did not stop. I was puzzled, because I was sure I had tested this before and the wiper would not operate with the switch in closed position. Looking back at my post, I'm not sure I ever actually tested this with the switch in place, but I instead had tested with a jumper in place of the switch. In any event, it looks like the switch is definitely bad, as when I checked across the terminals I got 12V even when toggling the switch, regardless of position. I disconnected the switch and ohmed it out, and sure enough it was now a solid open, regardless of the switch button being in or out. So it looks like I have a bad switch now that I should replace. It looks like I have to take the latch off (4 screws?) to access the switch. Anything I need to be aware of before taking that off, or is it just bolt on/off? Regardless of the switch problem, I don't think that explains the root of the wiper never turning off. The switch should be an open when the hatch is closed, allowing the wiper to operate. The switch would never be closed so long as the hatch is closed, so effectively, the wiper should think the hatch is always closed with the switch being in the stuck open position. This should not prevent the rear wiper from turning off. While I had the switch disconnected, I went ahead and tested the relay by shorting the switch connector with a jumper. I could definitely hear the relay toggling, and the wiper would not operate regardless of the dash switch position with the jumper in place. It got dark before I could take any more voltage readings.

I do have easy access to the relay through the little removable door just in front of the turn signal. I have had that relay exposed during my testing. I don't recall ever hearing it click, but I can't say for sure that I've actually been back there during the right conditions. It's easy enough to replicate, so I'll do that first chance I get. While I'm at it, I'll also check all the voltages at the relay to make sure I don't see anything abnormal there. I don't see a switch for the rear tailgate itself, so I'm assuming it being open shouldn't impact anything. Based on my earlier tests, I can say for sure that when the hatch was open, the wiper shut off, and would not operate in any position of the switch. This also dropped the voltage on the white/blue wire at connector #211 to 0V from the 9.1v.

Hi, I haven't finished reading the rest of your post yet, but I wanted to be sure we're on the same page first by clarifying something. The wire on dash switch (connector #211) where I'm reading the 9.1 volts is the white/blue wire (pin 1), not the blue/white wire (pin 2, I believe). Hopefully I didn't screw that up somewhere in my postings. According to the diagram you provided on EL-70, this goes to the amplifier. I don't see where it goes anywhere else. Since everything else on connector #211 showed either 0 or 12v, then I'm assuming that 9.1v is an output coming from the amplifier (the switch itself tested good, per my earlier post). Am I missing something here?

See my post 3 posts above your last one. Initially, I tested the switch with the switch disconnected. That's when I observed the initial fluctuations on the switch with the hatch open (switch closed). I cleaned the switch up the best I could, and then got stable readings (~0.8 ohms with switch closed, and OC with switch open). With the switch disconnected, I decided to test the wipers with a jumper in place of the switch, as you suggested here. That did not resolve the issue, and rear wiper still would not shut off. I also note here that with the switch disconnected (this should correspond to glass hatch shut), the white/blue wire on connector #211 still read 9.1v. When I jumpered the switch connector (hatch open), this voltage dropped to 0v (and inhibited rear wiper operation, as it should). The 265 ohms I read across the switch was after my jumper test failed, and yes, this was with the switch connected (and relay connected). I will check the voltage across the switch as you suggest later tonight, hopefully. I'll also check red/green at the switch. Reading back, I just noticed that I did check the red/green lines at the relay, and they did read 12v, so I expect it should be fine at the switch as well. I guess one thing I keep wondering is why the 9.1v on the white/blue wire at connector #211? While I don't know exactly how that amplifier works, I note that the white/blue wire goes between the dash switch and the amplifier, and does not appear to go anywhere else. So my question is then whether the white/blue wire is an input or an output of the amplifier? If it's an output from the amplifier, wouldn't that mean a problem with the amp? Or perhaps that output is dependent on the inputs to the amp? I was hoping to avoid it, but it seems like I'm going to have to take off those side panels to get to that amp and take some readings there. I can also ohm out the white/blue wire with the dash switch & amp disconnected, to verify whether any wiring issue there, as well as all the other wiring. Then, if all the voltages at the amp seem normal and I don't see that ~9.1v somewhere, then it seems like it would have to be an amp issue. I'll double check again, but as I recall all the voltages at the relay seemed normal. For the wiring between the roof/hatch, there looks to be a rubberized conduit through which the wires pass. It doesn't look damaged in any way, but that doesn't mean the wiring inside might not be. I think getting access to the amplifier and connections there may be necessary at this point.