Slartibartfast

I think the four-cylinder trucks got the C200 rear end, which does use a crush sleeve. There's a data plate near the wiper motor that should have the gear ratio (HG43 or HG46) if you'd rather track down a used rear end than rebuild yours. If these were available with the V6 in your market, you may be able to track down the H233B rear end, which does not use a crush sleeve. LSD is marked by an orange sticker that says "use LSD oil only," but you should be able to tell by trying to spin a rear wheel by hand with the rear end jacked up. If it spins the other wheel the other way pretty easily, it's an open diff. I haven't found a full service manual for the diesel trucks, but this manual covers the engine. The '90 US-market service manual from cardiagn.com or the '94/'95 from Nicoclub should get you close enough on the rest of the truck. The PD section covers the rear end. Fog lights are a pretty common option, at least over here. Different bumper inserts, relay near the wiper motor, rocker switch on the console, little added wiring. That harness was bundled with the alarm system on mine, suggesting it was installed at the same time, probably by the dealer. Neither system is in the service manual. The only black and red switch I remember seeing on one of these was a Russian (?) market hazard light switch. If your mystery switch isn't the same style as the rest of the dash switches, I would assume the PO added something. Follow the wires. And yeah, gotta host pictures elsewhere and link them in, unfortunately.

I haven't tried swapping calipers, but I do have some WD21 front brake parts laying around. Let me know if you need measurements.

The switch, yeah. Square-dash has a rocker switch on the dash, round-dash moved it to the end of the wiper stalk. The wiring to the amp looks mostly the same, but it's hard to say for certain given the different switch and the stuff they added to make that work. That's a good idea. I'll have a poke at mine later and see if passes one or both tests. Might also be a good sanity test for if we've got the test procedure right.

Haven't seen Pete around in a while. This should have what you're after.

Heat and torque. Aluminum and steel can get pretty stuck on each other. If it won't break free, try turning the other way, then back again. I got lucky on a brake line the other day by getting it hot and melting candle wax into it. Took a while, but came out without breaking anything.

Sounds like the relays are ruled out then. How are you with troubleshooting circuit boards? My next step would be trying to draw out as much of the circuit as possible, to see how power should be moving through it when it's wired up for the test, then go through that path with a meter to see if you can find where power (or ground) is getting hung up.

Should be good enough.

Wow. Yeah, that's not right. I'd be interested to see pictures of the insides to see what let go. Make sure your diff donor has a V6 (four-pots got a smaller front diff) and the same number on the data plate by the wiper motor. HG46 is 4.6 gears, HG43 is 4.3 gears. I've worked on a couple of GM 4.3s. Shakes like hell because it's a 90* V6, weird fuel injection. That said, they do have some decent torque. Someone on here had a 4.3-swapped WD21 around when I joined up, though naturally I don't remember their username. I think there was a solid axle swap involved.

NPD lists 92600-57G00. Still available, possibly because they want so much for it. Weird that the thermal protection switch is missing on the aftermarket ones. I wonder if they built it into the coil, or if they just didn't bother with it at all.

Yeah, that could explain a few things. The wire is a good get-you-home fix, but I recommend picking up a replacement ground cable, or at least a new terminal end.

I think you've got the pinout wrong. This datasheet for a similar-ish PN shows the same pin arrangement as the eBay listing (except that the #4 pin that's stumpy on the eBay ones is full-length). Looks like 2 and 5 are coil, 1 (at the end, between 2 and 5) is common, 4 is normally closed, 3 is is normally open. 2 and 5 should make it click, 1 and 4 should have continuity when the coil is not powered, 1 and 3 should have continuity when the coil is powered. Worth noting that testing components in the circuit can be confusing as hell, as other components and connections do things you don't expect. It may be necessary to desolder the relays and test them off the board. Probably safer for the other components on the board as well. The buzzing sounds like you're energizing the coil through the normally closed contact. Coil gets power, contacts open, coil loses power, contacts close, repeat however many times a second. Same as how a horn works. Clicking suggests at least one of them works. Hopefully the other one is the problem. The amp failing both versions of the test suggests that you're looking in the right place.

Lots of good info around here for R50s. Download the service manual from Nicoclub if you haven't yet, may come in handy with the engine swap. I don't think I've heard of a power valve screw locking one up before, that's gnarly. Your pictures aren't showing up for me.

I dug out the '87 paper manual. The diagram looks the same, but the test is not. EL-89 in the '87 manual wants the test light across 2 and 4, not 2 and 7 like the later manuals. Give that a shot and see how it goes. Unfortunately it's got the same head-scratching description. (And it calls the box a relay rather than an amp, despite using the same drawing.) I don't know why the test procedure is different. The wiring for pins 2, 4, and 7 goes to the same places in either diagram. In fact I can't find any difference between the '87 and '89 rear wiper wiring diagrams. The '90 diagram has some routing/plug differences but looks like a different organization of the same bits. '95 complicates things by moving from a nine-pin switch to a four-pin switch with a diode and another relay making up the difference, but the wires from the amp all appear to go to more or less the same places. So, again, I can't say with any certainty whether the '95 amp on my bench would work in your '87. Speaking of head-scratching, the test does not specify whether it's for the front or the rear wiper amp. Both amps use an eight-pin plug with one pin missing, but the front amp is missing #4, and the rear amp is missing #8, and the test diagram clearly shows a plug missing #8, suggesting it's gotta be the rear amp. There does not appear to be a test diagram for the front amp. I bought a set of cheap jumper leads a while back, and was surprised to find that they were made with iron-core wire. I've taken apart some cheaply-made junk, but that was a new one. I could pick up the wire with a magnet, and they melted really easily. But, yeah, better to smoke a cheap jumper than blow up the meter, or an unobtanium wiper amp from the '80s. My usual trick is forgetting I had the meter on amps and blowing the fuse trying to test voltage. What's on the board? Any obvious relays in there? If you can work out which pins should be open/closed when the relay isn't energized, and test across those, you should be able to work out if one of them is stuck on.

Keeping older rigs alive can be a bit like playing whack-a-mole. Hopefully the MAF mole stays down for a while! When my stock 70A alt started making threatening noises, I swapped it for a 90A Maxima alt. Plugged right in. IIRC it was actually cheaper that the 70A. I don't know that the truck needed another twenty amps of headroom, but it's got it now. I don't remember if there's a similar parts-bin upgrade for the R50, but it might be worth looking into if you've gotta get in there anyway.

I found it, but I can't guarantee it'll work in yours. The sticker says 28510 83P00 ('89-'95 according to NPD). Replaces 28510-83G00 (also '89-'95). Not listed with yours. The one that replaced yours (B8510-42G85) is listed for '87-'94, suggesting that there wasn't a design change in '89. 43G85 also replaced 28510-30R00, '89-'95 Nissan Axxess (a model that I didn't know existed until just now), which is not listed as fitting an '87 Pathfinder, which makes me think their compatibility check is whether it's original equipment, not whether it'll work. I would be kind of surprised if the 83P00 didn't work in yours--but at the same time, not that surprised that Nissan found another dumb thing to change for no obvious reason. I'll dig out the '87 manual later and see if the wiring diagram looks the same. It might be worth seeing if you can get yours open. If it's like the door lock timer, the plate where the plug is should sorta pry out where it's snapped into the box around it, and then the whole circuit board and plug should just slide out. Might be something obvious and repairable. Relay welded shut, cracked solder joint, capacitor dumped its guts, something like that.

Mine's needed this done for longer than I've had the truck. I bought gaskets, studs, and a 90 degree drill adapter shortly after we got the truck, and then I never got around to it. My engine is also a little tired, and the rear main is leaking, and I've got a VG33 in the corner waiting for me to get around to it, so chances are I'll keep ignoring the exhaust leak until I'm ready to swap the engine. The VG33 has a little more displacement, larger exhaust manifold studs, a larger crank snout, a better oil filter location, and a couple of other minor improvements. It's mostly bolt-in, and will run off the stock harness/computer/fuel system if you swap a few things over from the old engine. It's also got flat belts, and a different balancer, so there's a little screwing around required there. David Carroll/Mr. 510 makes (made? Don't know that he's still selling them) adapters that replace the balancer so you can run the old V belts and accessories. You will need to modify a VG30 water pump if you do it this way. (Details in Mr. 510's VG34 build thread.) I have read that the Xterra/Frontier accessories and brackets will fit in the WD21 engine bay, but the R50 Pathfinder ones won't, though I think someone managed to make them work with a little modification. I have heard of people swapping the VG30 crank into the VG33, to keep the old balancer, but it sounds like a lot of work to use an inferior part (the smaller snout of the VG30 crank does sometimes have issues). The VG30 cams are supposed to be a drop-in upgrade over the VG33 cams, so hold on to those. The oil pan and pickup may need some screwing around depending on your donor. I've read that VG30/33 heads can be swapped, but the cooling passages are a little different due to the larger bore, so it's not exactly ideal. If I was going to pull a head, I'd just fix the old head on the bench (without a truck in the way!) and then put it back on.

The Terrano is just what they called the Pathfinder in some other markets. I may have one off my parts car. I'll dig around later and see if it's got a part number on it.

I've been ignoring the same problem for years. Busted stud, same as yours (same one too, I think). It's dead common on these. The studs were too small or the wrong steel or something. The next version of the engine (the VG33) uses larger studs, not that this helps you any. My dad had the same problem on one probably twenty years ago, and had a shop cut an access hole in the inner fender to make it easier. I bought a 90* drill adapter to try and do mine without cutting sheet metal, got some 300ZX exhaust studs (IIRC they're supposed to be stronger?) and new manifold gaskets, and then never got around to it because it looked like a PITA and it wasn't obviously hurting anything. I don't think I've ever heard of one of these burning an exhaust valve. There's also a common exhaust leak at the Y-pipe, under the driver's floor. Tends to rot out the floor under the driver's right heel. That one will set your carpet on fire if it gets bad enough.

Yeah, that sounds like the MAF rather than the connector. Does the MAF look okay? Any fouling on the elements? I don't know what would've killed it (or dirtied it) that fast, though I remember seeing a picture where someone got a fly stuck in one (don't think it was an R50) due to an air filter box not sealing properly. Hopefully the new one holds up better.

I wish the service manual gave part numbers! Or at least a spotting guide for when they list different models of the same part with different torque specs. I had a look at the hatch glass latch from my partsfinder ('95, same as my '93, hopefully the same as what you're working with). The bad news is that the switch is built into the plate under the latch, and the plate appears to come with the latch assembly (either 90330-41G00 or 90330-41G01 for an '87)... or would, if they weren't discontinued. The good news is that it's a very simple switch. Unless the contact fell off the plunger, or the plastic broke, I imagine it's just got some corrosion where the contact hits the body of the switch. Should be easy to inspect and clean once it's off. (After looking at it again, I would leave the adjustment bolts alone, and pull the latch and plate as a unit. Four bolts, one plug, and of course the linkage.) Clean up the contact points and the slots they go into with a small file, steel wool, a strip of sandpaper, a fiberglass pencil, something along those lines. That should bring it around. I would also check that the linkage from the latch isn't pressing on the plunger when the latch is closed, though I'd be surprised if that had somehow gone wrong. The cargo light switch is built into the main hatch latch. Again, it's not replaceable on its own, though it looks like that assembly is still available (in three different variations, for some reason). If you look into the latch from the outside, where the striker goes, you'll see a big rubber chunk in there on one side. The striker is supposed to push that chunk inwards when the hatch closes, which opens the switch contacts. But it's a stupid design, and the rubber wears, and eventually it doesn't open the contacts like it's supposed to, and the cargo light starts flashing when you go over bumps. I imagine the previous owner got tired of the light show and unplugged the bastard. You may be able to clear this up by adjusting the striker. Mine has tape wrapped around the striker, which also works. Again, I am assuming that your '87 is built the same as the four-doors I'm used to. Your cargo light has a three-position switch on it, right? Looks like the instructions for testing the amp didn't translate well. I think they meant that grounding pin 6 (with the rest wired as shown) should make the lamp come on.

These only have a camshaft position sensor. It's inside the distributor. It's an optical sensor, like what's in an old computer mouse with the ball in it, not a hall-effect like most other stuff. There's a plate under the rotor in the distributor, and the sensor is under that. I've heard of them acting normal when cold but playing up when warm, which sounds like what yours is doing. Check the bearings while you're in there, especially if you find debris under the plate. I don't know whether the worn bearings take out the sensor, or just confuse it. That said, if the starter is struggling/engine is turning slowly/it won't start without a jump, that's not the cam sensor. I would check that the battery is good, and that the alternator is charging it when the engine is running. I recommend downloading the service manual. Free from either cardiagn.com ('90 manual, if yours is square-dash) or Nicoclub ('94/95 manual, round dash). EF&EC is your friend for engine control questions. Sorry to hear it got "rebuilt" with worn-out junk. One of my dad's friends bought a Triumph like that. I think it was assembled with the parts left over from rebuilding a few others. It ran surprisingly well, other than the alarming clacking noise, the clutch that didn't disengage all the way, and the steering column that was about to fall out. It took us a while to sort it out, but it was a nice driver when it left. Hopefully yours comes around too.

Interesting. Agreed that it shouldn't be the problem, but odd that it's out at the same time. I guess it could've been out for quite a while without being noticed. I've had the latch off of mine a couple of times (I added a second switch to it so it turns on the cargo light when it's unlatched), and I don't remember it giving me too much trouble going back together. The four bolts on the plate shouldn't give you a problem. The two holding the latch to the plate have slotted holes for adjustment, so draw around the latch (or the bolt heads) with a marker before taking those out so you can put it back where it was. I had a look at mine to refresh my memory on how the wiper's supposed to work. With the switch set to intermittent, the motor turns counterclockwise (from my viewpoint under the hatch), and the linkage stops just short of the lockout switch for the hatch popper. When I turn the switch off, the motor turns clockwise, parks the wiper, and depresses the switch. This confirms that the gap to your hatch popper lockout switch is normal, for whatever that's worth.

I haven't worked with the R50 fuel injection, but my WD21 acted up (low idle/stalling, but normal power off-idle) when the MAF connector was worn out. Wiggling the connector would bring it back for a while. Messing with the contacts in the connector cleared it up temporarily. After a while I got around to replacing the connector with one that fits snugly and doesn't shake around, and it hasn't acted up since. I don't know that this is your issue, but I would try screwing around with the connector to see if that clears it up for a while. If it does, could be it's the screwing around with the plug, not the new MAF, that's been bringing it around each time. If not, might be worth tracking down an OE MAF. Random misfires makes sense if it's struggling to run with an inaccurate idea of how much air it's getting. Knock sensor is likely unrelated.

Yep, I got those crossed up in my mind. Good catch. Looks like the dash switch grounds that wire, so I'm guessing there's some transistorized something or another in the amp (not just relay logic) that's applying a little voltage to that line so it can tell when it's grounded by the switch. I would assume that's normal. There is a switch for the tailgate (built into the latch), but it's not part of this circuit. Sounds like the switch for the hatch glass is doing what it's supposed to do. Hopefully the relay gives you a smoking gun.

Sorry I missed that. This kind of thing is a pain to diagnose over the internet via text, especially given how unexpectedly complicated this wiper circuit is. Blue/white doesn't go to the amp at all. Green/red carries fused + to the glass hatch switch. When the hatch is shut, blue/white carries power from the switch to the relay coil (you should be able to make the relay click on and off by playing with that switch) and to the switch on the dash. If the switch is set to on or intermittent, it connects blue/white to red/blue, which goes back to the relay, through the normally open contacts (closed now that the relay is active), to green/red, the fused + feed again. All I can figure is that this is latching the relay--so if the relay is engaged (ignition on/hatch closed), and the rear wiper is on or intermittent, opening the hatch switch won't disengage the relay, because it's passing power to its own coil, effectively bypassing the glass hatch switch. This would make the wiper keep going if you opened the hatch with the key, which seems like it would be a bad thing--though I guess you can't open the hatch with the key when the key is in the ignition. There must be some reason it's set up like this--but I don't think that rabbit hole has the answer to this problem at the end of it. (Assuming I'm following the lines on the diagram correctly.) The takeaway I'm going with is that power on blue/white should make the relay click. If the relay isn't working, and it's leaving the normally open contacts closed when the coil is powered, it would be applying fused + to blue/black. I have no idea what effect this would have. Might be confusing the amp? Pull that trim panel, test the relay. Make sure it's good, and make sure it clicks when you turn the key on with the glass closed. If the relay is OK, but it isn't getting enough power from blue/white to click, chase that low voltage. If it's working how it should, I would rule it out for now. It looks like I was wrong about the contacts on the motor powering it directly. Blue from the contacts goes to the amp. So the contacts don't run the motor directly--they tell the amp to do it. I'm also seeing a the blue/black wire, running to the "wash" position on the switch, which I assume grounds out that same blue wire when the washer pump is running. If blue or blue/black is grounded out, this would cause the amp to run the wiper motor whenever the ignition is on. Sounds like your testing has ruled this one out, though. The amp has pretty much full control of the motor. Blue/yellow goes straight from the motor to the amp. Blue/red goes to the switch, which grounds it (along with the white/blue wire to the amp) in the "on" position, or connects it to the amp via the black/blue wire in any other position. If the dash switch is good, and neither of the blue/black wires (there are two black/blue wires in the same plug) are grounded (telling the amp to run the motor), then, yeah, that points to the amp. The trim panel should come out without too much fuss. If it's like its counterpart in the four-door, it's just a grab-and-pull job, apart from the very back lower bit that's hooked under the plastic trim at the back of the cargo floor. If that trim has the same stupid plastic screws that mine does, I recommend a flat-blade screwdriver, with as little downward force as possible, until you can hook a fingernail under them. They push in, which makes them impossible to unscrew with a Phillips driver. It is possible to get the side panel out around the floor trim, but in my experience it's more difficult that doing it right.