charles Posted March 22, 2014 Share Posted March 22, 2014 Hello everyone; I just super sketchily 'fixed' my speedometer... after all sorts of chundering around, it turned out to be a bad wire somewhere between a harness in the engine bay and the super multiple junction (SMJ). The following is an unnecessarily detailed and illustrated play by play... bear with me as I use this as an excuse to practice posting with photos, etc. At the end of the day, it does work, but if I've done something daft that I haven't realized, please point it out! So... my cluster is a soup sandwich. Tac is intermittently spastic, speedo/odo totally dead, gas gauge iffy at best, and some lights sometimes not working. Tac and lights respond to smashing the dash, but the speedo is totally dead, all the time. I jacked up the back, threw it in 1st, and got a .5V AC reading off the vehicle speed sensor (VSS). I got the same reading at this harness in the engine bay, next to horn/light relays (picture taken later, after cutting wires, red and white from VSS): I could not, however, find the same reading at the SMJ (I eventually figured out how to read wiring diagrams, and figured, optimistically, that the wires went to K14 and M13). So, I connected tiny female disconnects to one end of speaker wire, put those to the pins in the harness from the VSS, and jammed the other ends into K14 and M13 in the SMJ. Lo and behold, putting the vehicle in 1st saw the speedo going to 10km/h, and the odo started to turn! So I spliced the speaker wire into the engine bay harness, cut the wires going to K14 and M13 and spliced into those too! This is maybe the sketchy part... I'm using speaker wire (so smaller gauge than the wire typically used) and it's running across the engine bay along the brake lines, under the rain tray, and then into the cabin through the port meant for the door's speaker wires (note the reef knots to tie the new 'speedo' wire to the speaker wire, which I then ripped back into the cabin...). I figure because the signal is low voltage/current, it's alright to use the thinner wire? Or maybe at high speeds the signal gets higher voltage? Is it alright to have current running next to brake lines? Anything else super stupid I've done and not realized? Finally, I'd like to put together a consolidated 'how-to' for diagnosing cluster issues. There's A LOT of info on how/what to do, but it would be nice to have it in one place, and have things in order to look at, from easiest and cheapest to diagnose through to hardest and most expensive. I counted out quarters at a wrecker to get a cluster (after tightening its screws, etc.) only to have it not make any difference. It'd be great if others could be saved the same fate! Feedback on this? Maybe I'll post a draft to this thread, people can chime in, then I can revise and then post? Anything particular I should know about the 'how to' section? Cheers, Charles. Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 6, 2014 Share Posted June 6, 2014 Very nice work around. I don't think the speaker wire will cause you a problem. I've got the dead speedo /odo too. I love to see a organized step-by-step how-to. Seems like most replace the cluster and/or the VSS but obviously from your description these are not the only issues that can be causing the problem. I struggle with wiring diagrams that you need a magnifier to read. Or maybe I'm officially old , lol Good pics too btw. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 7, 2014 Share Posted June 7, 2014 Looks fine to me, so long as the wiring isn't rubbing anything or snagging your feet. So long as the connections are done right and insulated it should keep working like it should. I wouldn't go super thin (no magnet wire) but the speed sensor's just a reed switch, so I can't imagine it passes much current. Nice to see I'm not the only one with zip ties holding the air vents in. I haven't had trouble with my dash (yet?) but if I do I'll post up what I can about fixing it. There isn't a whole lot of info about them up yet. Link to comment Share on other sites More sharing options...
ahardb0dy Posted June 7, 2014 Share Posted June 7, 2014 Good fix ! I would run the wires thru the main harness rubber on the pass side than across to the SMJ inside the cab under the dash, less chance of anything happening to the wire that way. I had zip ties holding my air vents down also, used black ones so you couldn't see them. Had a similar problem in my 90 sentra, brake lights wouldn't come on, traced the problem to a bad wire between the fuse block and brake light switch, bypassed the factory wire and good to go again !! Electrical is always a hassle, good job figuring out your problem and thanks for sharing !! Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 15, 2014 Share Posted June 15, 2014 I thought I would have a look and see why my speedo stopped working. I pulled codes 34 and 14. Knock sensor and VSS. I pulled the VSS and it looks OK to visual inspection. I am trying test for the 0.5 volt A/C by spinning the gear and checking with multimeter. I get nothing. I'm not sure if this is because my multimeter's lowest setting for A/C voltage is 200 and it just doesn't have the sensitivity to pick up the low voltage or I'm not spinning it fast enough (actually my wife has gracuously given of her time to do this,lol) I guess I could put it back in and try wth the rear end on stands and the truck in gear like Charles did. Wondering if anyone else has done this and gotten a good reading while spinning by hand? The pinion gear is in good shape and spins freely although there is a little "catch" as you spin it. Thanks Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 16, 2014 Share Posted June 16, 2014 My understanding is that the VSS is a simple reed switch. I'd put the meter on ohms (continuity setting if it has one, so it beeps when the circuit's closed), turn the gear, and see if the circuit opens/closes as you turn the gear. Link to comment Share on other sites More sharing options...
Slartibartfast Posted June 16, 2014 Share Posted June 16, 2014 Sorry, checked the manual again, the .5v AC test is correct. Sorry to cause confusion. It's drawn like a reed switch for some reason. The 200VAC setting might be too high to read half a volt. I would try putting it on lower voltage DC (about 20V on my unit) and then look for any reading at all. The numbers it gives you probably won't be correct, but if it doesn't register at all, you can probably assume the sensor's toast. Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 17, 2014 Share Posted June 17, 2014 Yep. I scored a new , more sensitive Multimeter at good ol' Harbor freight. 20% off for father's Day too ! Zero volts register when spinning VSS or when in truck with rear jacked and in drive. Ordered a new VSS. I guess I'll see if that's really the problem. Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 22, 2014 Share Posted June 22, 2014 (edited) Ok. Got the new VSS in and changed Transfer case fluid while I was there. Speedo and odo both working nicely again ! In comparing the old VSS to the new VSS there was definitely a difference in the way the shaft spun. The old one had a "catch" when spinning suggestive of bad bearings. I replaced the little snap ring that holds the pinion gear on the shaft with a 3/8" one. It was super tight and I'm a little concerned about metal fatigue and breakage. I tried the 7/16" snap ring and it was a little too loose IMO. So I'm guessing the snap ring is metric. Does anyone know the exact size? Went to AZ and Advance - neither one carried assorted snap rings in metric. Guess there's not too many of those new-fangled Japanese imports on the road as yet! Edited June 22, 2014 by JackStraw1 Link to comment Share on other sites More sharing options...
Kingman Posted June 22, 2014 Share Posted June 22, 2014 10mm Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 22, 2014 Share Posted June 22, 2014 Thanks ! Link to comment Share on other sites More sharing options...
adamzan Posted June 22, 2014 Share Posted June 22, 2014 Ok. Got the new VSS in and changed Transfer case fluid while I was there. Speedo and odo both working nicely again ! In comparing the old VSS to the new VSS there was definitely a difference in the way the shaft spun. The old one had a "catch" when spinning suggestive of bad bearings. I replaced the little snap ring that holds the pinion gear on the shaft with a 3/8" one. It was super tight and I'm a little concerned about metal fatigue and breakage. I tried the 7/16" snap ring and it was a little too loose IMO. So I'm guessing the snap ring is metric. Does anyone know the exact size? Went to AZ and Advance - neither one carried assorted snap rings in metric. Guess there's not too many of those new-fangled Japanese imports on the road as yet! I don't understand how in 2014, when pretty much all manufacturers use metric, metric hardware is still not commonly available. I mean most "hardware" stores around here only carry the crappy 8.8 metric hardware which is basically grade 5 SAE. Link to comment Share on other sites More sharing options...
JackStraw1 Posted June 23, 2014 Share Posted June 23, 2014 Agree. It's really ridiculous. So many cars with all metric parts and no one had these where I live. Makes you really wonder about who decides what goes on the shelves. I did find a assorted set on Amazon for $7.00 and change. I think I'll just go ahead and get it. I'm always losing these things. Link to comment Share on other sites More sharing options...
Precise1 Posted June 23, 2014 Share Posted June 23, 2014 I don't understand how in 2014, when pretty much all manufacturers use metric, metric hardware is still not commonly available. I mean most "hardware" stores around here only carry the crappy 8.8 metric hardware which is basically grade 5 SAE. You can't commonly find decent metric hardware in Canadia? B 1 Link to comment Share on other sites More sharing options...
ahardb0dy Posted June 24, 2014 Share Posted June 24, 2014 You can't commonly find decent metric hardware in Canadia? B like that one !! Link to comment Share on other sites More sharing options...
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