My lockers have been intermittent, That is, they were engaging and disengaging inconsistently. Sometimes they work fine, sometimes they would not engage, sometimes they would not disengage and sometimes they would be half engaged which was a little un-nerving as they made lots of metal on metal noise and I was sure they were disintegrating.

So here is my troubleshooting tree that eventually led to resolving the issue

1. Disconnecting the airlines always fully disengaged the lockers - ruled out a mechanical "sticking" issue in the locker itself.
2. Found oil in the air lines and at the solenoid valves.
- thought maybe that maybe there was a lot of oil in the lines that was not moving - preventing disconnect of the locker
- Cleared the oil from the valve and air lines by disconnecting the lines at the diff and blowing it out from the top.
- found a fair deal of oil in the lines, but it was not filled, which might have explained the problem.
3. Measured the voltage at the solenoids, 5.5 volts, seemed a little low, but I wasn't sure what the correct voltage should be,
4. Pulled up the ARB wiring harness diagram on the web.
- ARB wiring harness seemed to be ok everywhere I looked.
- There are really only 4 wires that have to be connected to the vehicle. Compressor power positive and negative, switch lighting and solenoid power.
- Couldn't see any reason that I shouldn't be seeing 12 volts at the solenoids. There are no other components that would explain a voltage less than 12v.
- Compressor power to the battery was ok.
5. Took the AC/Heat panel off so I could inspect the wiring behind the ARB switches.
- Switch lighting was tied into the back lights for the heat/ac controls
- Relay power tied into the fan control input, the middle speed control. hmmm what voltage is that providing.
- voltage was 5.5 volts, but dropped to about 1 volt when the fan was on the 3 setting
- About 3 months ago I replaced the fan resistor after speed 2, 3 and 4 stopped working.
- Replaced with a Sebring resistor block, much better built, but with slightly different resistor values than stock

So the shop that installed my lockers first tried to tap the cigar lighter power for the control circuit as evidence by the marks on the positive wire, but found it wasn't a switched circuit, so they tapped into the fan control. Not sure why they picked the middle leg, for speed three, but it worked fine for two years, until I replaced the resistor block, then the voltage at the switch was too low to activate the solenoids.

So the fix was to run a new circuit back to the junction panel and using an Add-A-Circuit to provide a separate 12v input to the switches. Definitely a bad decision to tap into the fan circuit.

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2005 CRD "Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.