TPM malfunction - RDC failure questions - FIXED!

[KellyF]

So I started checking continuity on the twisted pair today. I found 2 other modules in the R/H side of the cargo area, below the fuse box. They had twisted pairs of the same colors going to them. I looked at wiring diagram on newtis and saw that they were all on the same bus. I checked continuity between like colors between those 2 components and got 0.1 ohm. When I checked between my RDC plug and either of those, I got an open. Looked around underneath the car and found more chaffed wires about a foot from the damage I found last week. Unwrapped the whole harness and found the twisted pair damaged and one wire broken in two. Temporarily spliced it together and the RDC now shows in the module scan. What is the correct procedure to repair these CAN bus wires?

[andrewwynn]

i use crimp on butt splices with heat-shrink and weather seal built in; they are good for under water use; when you head-shrink they basically glue themselves onto the insulation.

cut the wire if you have enough length so the 'bump' in the two wires don't align next to each other for a more compact fix; you can put a bigger heat shrink over the whole batch to make it even cleaner.

[KellyF]

Originally Posted by andrewwynn

i use crimp on butt splices with heat-shrink and weather seal built in; they are good for under water use; when you head-shrink they basically glue themselves onto the insulation.

cut the wire if you have enough length so the 'bump' in the two wires don't align next to each other for a more compact fix; you can put a bigger heat shrink over the whole batch to make it even cleaner.

These wires are small - .35mm, which works out to 26-28 AWG. Do they make those splices that small? Also, I was planning to put it all in one of those corrugated slit conduits. For some reason, there was damage at 2 of the 3 locations where the bundle was secured to studs on the frame. And the weird thing is, it looks like the plastic "saddle" type support is what damaged the wires. I figured I'd put it in a conduit and zip tie it to the original support clips.

[andrewwynn]

Pic was a good macro they looked like 18ga. For wires that small I use telephone butt splice gel filled water proof connectors (the little circle ones you crimp on with a pliers you don't strip). You need a little extra length because the wires go in the same side of the splice. shrink around the bundle to strap against motion.

[KellyF]

Originally Posted by andrewwynn

Pic was a good macro they looked like 18ga. For wires that small I use telephone butt splice gel filled water proof connectors (the little circle ones you crimp on with a pliers you don't strip). You need a little extra length because the wires go in the same side of the splice. shrink around the bundle to strap against motion.

Yeah, I've used those before. Probably would have been easier in the end. I had some butt splices that were good for 20-26 gauge. They have a heat-shrinkable outer sleeve, but are probably not waterproof. I used those for now, but when I was stripping one of the wires to splice, it broke about 1.5" behind where I was stripping. Looked like the center conductor was already broken and the insulation was all that was holding it together at that point. I ended up shortening both wires about 2". Put them in a piece of corrugated conduit after I got them spliced back together. Had to turn the mounting bracket around so the wires would reach. Reset all the faults and it works like it's supposed to. I may try to get a good harness from the junkyard and replace the whole section, since 3 of the 4 wires have splices in them now. I don't have a lot of confidence it their long term reliability. But, for now, it's working.

Thanks for your help,
Kelly

[andrewwynn]

I'd have probably soldered but good job. What the heck is RDC it's not ringing a bell.

[KellyF]

Originally Posted by andrewwynn

I'd have probably soldered but good job. What the heck is RDC it's not ringing a bell.

RDC is the TPMS controller.

[ard]

Originally Posted by andrewwynn

I'd have probably soldered but good job. What the heck is RDC it's not ringing a bell.

Reifendruckkontrolle

FWIW

[andrewwynn]

I figured as much like Drive Away Protection is "EWS" of course. I was thinking it was back up beep. I have 01 with no TPMS or even the precursor which uses tire rotation to meausre if a tire goes flat.