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Lighting & ElectricalPost your lighting and chassis/engine electrical questions here. Any audio/video questions should be posted in the 'Audio/Video Electronics' section.
Then you most likely have a short in the wire from the fuse block to the VSS. It is probably corrosion under the fuse block or the wire in the loom going to the transmission. There are a couple of ways to do this. If it were me I would not unbolt the fuse block and bend it up unless I knew for sure that this is the problem area because there may be unintended consequences. If you go that route use a mirror and minimize the trauma on the wire loom.
I would open the loom just after the fuse block and try to locate that wire. Your tester might be able to help you here. If not then it’s probing same colored wires in resistance mode with the other meter lead down at the trans. It’s a big wire loom so that might be a challenge. The problem sounds intermittent so you may or may not be able to find it on any given day but I am 90% sure that this wire needs to be replaced. You will need proper soldering skills and shrink wrap tubing to do it right
George
Am I correct in believing it’s the purple wire I should be tracing? I was trying to determine which direction it takes from the fuse block but it was too close to the tone generator so I kept getting interference from it. I believe it’s in the bundle running along the driver’s side fender back to the firewall. I could spot where it heads upward around the driver’s side of the transmission from below but I wasn’t able to see where it emerges in the engine compartment.
It seems like the path of least resistance would be to just run a new wire (soldered and heat shrinked). I’d prefer to find the damaged portion beforehand because there may be additional wires in the harness showing damage in the same area.
Yes it is the solid purple wire. I dont know the routing unfortunately. Yes it would be best to find the damage for the reason you stated. There are a few different ways to go about this, let me know if you get stuck. You may have a fused jumper wire in your future.
Yes it is the solid purple wire. I dont know the routing unfortunately. Yes it would be best to find the damage for the reason you stated. There are a few different ways to go about this, let me know if you get stuck. You may have a fused jumper wire in your future.
George
I didn’t get the opportunity to dig into it last weekend, did a silly thing like get up from a bench and threw my back out.
Do you happen to know what gauge that sensor wire is? I’m happy to hear any advice as to how to proceed before I get started. Ideally making up a wire run (hopefully purple if I can find a roll of it) with an inline fuse holder from the draw side of the crank fuse to the connector on the NSS.
I don’t really want to cut the wire or jacket but I’m not sure if there is a good way around it. On PC molex connectors I’ve been able to push out a contact and replace it - I’m not sure if that’s possible with these weatherproof connectors. I can find replacement plugs and pigtails which would at least provide the correct terminal.
I dont know the gauge but 18 stranded should do. I would identify the wire just after the fuse box and probe it to check for a short to ground with the VSS disconnected and the fuse pulled. Move the wire loom around to see if you can get it to short. If so then cut the wire 4-6" from the box and repeat the test on both ends to see if the problem is in the purple wire run down to the VSS or the short remaining run under the fuse box.
I haven’t satisfactorily resolved this issue yet. I haven’t been able to make it blow a fuse since last fall but I’ve also only driven it a few times since then due to concerns about not being able to get it started for a return trip. No luck in finding a short on the purple wire despite any amount of moving the harness. I ended up unbolting the fuse block and moving that as well and still found no short to ground on that line.
Am I correct in believing the TCCM is also served by the same purple line? Mine has the four button AutoTrac controller. I spotted two solid purple lines at terminals C13 and C11 but the AutoTrac wiring diagram only seems to show the extra circuits differing from the two-speed T-case controller. The standard diagram shows a purple line going from D16 to the CRANK fuse but mine has a light blue line at D16 and a black/white at C16 - at least if I’m reading the labels right.
This TCCM box was installed circa 2011. The previous one and the encoder motor stopped working and left my t-case locked in low range back then.
If I understand the history correctly then the crank fuse blows with the NSS disconnected therefore the problem is corrosion under the fuse block or the dedicated ppl wire from the crank fuse to the nss. No other function exists on that wire. This experiment would prove the fault:
Pull the crank fuse. Solder a fused take off wire to the power side tab of the empty fuse socket using the crank fuse value and run that 18 gauge wire down to the nss. Cut the ppl wire that comes from the crank fuse a few inches from the nss for easy reattachment and solder the jumper to the nss pigtail. This will not only prove where the fault is but will give you a temporary reliable solution.
This evening I cut the purple wire at the NSS, ran a new wire in a split loom up the frame rail to the fender well, soldered in a weatherproof mini-fuse holder and then made a fuse tap by soldering and heat shrinking the wire to a blade extracted from a blown mini-fuse.
I tested continuity half a dozen times with each step to be sure I wasn't missing anything. It fired up the first try once I had it all buttoned up. All that remains is to drive it and see what happens.
As an aside - when I opened up the wire loom coming from the right side of the fuse block I discovered there are four purple wires in there. Again, I appreciate the advice with this.
