ARB/ Ground Wire and the KISS principle
Especially the latter! Here is the story:
Alec(ccbruin) had contacted me about looking at the ARB set up on his Jeep which he had been having problems with. He brought it over to me yesterday and I started poking around. The compressor wasn't working and there were some other issues. One of the lines had become disconnected from the compressor and I cut and reattached that, taking apart the other fitting and reinstalling that also. I then moved onto the compressor electrics.
The relay wasn't getting enough juice, so I bypassed the relay. The compressor worked. I then tried a couple of different relays, but had no luck. Chris (the Elder) dropped by and we both tried various combinations of jumping, relays, etc, finally coming to the conclusion that the relay plug itself was the problem. Since I had another ARB harness, I clipped out the old part and wired in the new one. Same problem: bypassing the relay turned the compressor on. Tried other tests and jumping and the same issue, coming to the conclusion that all the relays that we had available (4 in all) were all bad. Just as we were about to go to the auto store and grab a new relay, Chris says the magic words, " What about the ground wire?"
Yeah, no ****. What about the ground wire? How many times have Chris, myself and everyone else said, "Check the ground wire" every time someone sparks up about an electrical problem? Adam (SUNK) would have hung his head and walked away....So...we jumped the existing ground to a new ground and everything worked fine. All the relays also worked fine. I reinstalled the wiring, complete with a new ground wire, and tested the ARBs.
The front worked fine, but the back wasn't locking in. I pulled the air line from the back diff and it was filled with diff oil...a lot of diff oil. This is a small, but recurring problem with ARBs, and can be caused by either too much or too little diff oil. ARBs are very sensitive to the amount of diff oil, BTW. I pulled the line from the compressor, sprayed some solvent down into the line and then blew the line out with compressed air. I reinstalled the line after checking the fluid (low in this case) in the rear diff, and checked the ARB again. Now the back was locking in.
Moral: If you have a damn electrical problem (and this is something that both Chris and I know) ALWAYS CHECK THE GROUND FIRST.
And Chris and I can hear you laughing from here, Adam....
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