I am trying to get my center differential lock working after some work on my dash. Background is that it's a '91 80-series with the pin-7 mod done. It was functional before I did the work. I removed the dash to apply sound deadening to the firewall. I reassembled everything and now the diff lock doesn't work. Pushing the CDL switch doesn't light up the switch or the dash. There is no noise from the CDL motor and no driving changes characteristic of a locked center differential. All of the wiring visible behind the left kick panel appears to be undamaged and plugged in correctly. I tested the CDL switch and the CDL relay box behind the kick panel according to the FSM instructions. Everything passed (barring the failed FSM test due to the pin 7 mod). The weather is not conducive to me rolling around under my truck at the moment (snowing and no garage or carport). I doubt there's an issue there because the problem manifested AFTER my dash R&R. I suspect a wiring problem somewhere between the I have what I think are the pertinent pages from the EWD, but it doesn't give a good idea of how the CDL switch ties into the rest of the circuit. I need to know what voltage or continuity to expect at what pins on the switch and relay in engaged and disengaged mode so I can track down where the problem is. Does anyone have a block diagram of the switch in relation to the relay? Thanks in advance!
CDL Not Working ('91) (1 Viewer)
- Thread starter Izeloz
- Start date
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My question is - all 91/92 cruiser came with a CDL switch installed. So i am confused when you mentioned pin - 7 mod done to a 91?
Also if you manually put the car on 4L, did the CDL light come on the dash?
Also if you manually put the car on 4L, did the CDL light come on the dash?
Sounds like a missing ground.
- Thread starter
- #4
I will recheck all ground points, but I'm 90% sure they are all there. Also, '91-'92 did come with a CDL switch OEM, but it only allows you to manually override the diff lock in 4lo. You can't engage the CDL in hi range regardless of switch position unless you do the pin 7 mod. The dash light doesn't come on when pushing the switch or putting it in 4lo. I drove all over my neighborhood in hi and lo pushing the switch repeatedly like a mad man, in forward and reverse gear, until my neighbors probably thought I was crazy (err...more crazy than they already must think I am).
This is 100% wrong.
In a standard unmolested configuration, the CDL switch allows you to lock the center diff in high range. The CDL automatically locks in low range.
The pin7 mod does nothing for a 91/92 other than allowing you to now unlock the CDL in low range.
All that is needed for a 91/92 is to remove the low range sensor plug on the transfer case. Since the A440F is not electronically controlled, the pin7 mod does not apply.
Simply unplugging the low range switch on the transfer case enables you to have full manual control of the CDL in both high and low range. It is completely non-invasive.
Simply unplugging the low range switch on the transfer case enables you to have full manual control of the CDL in both high and low range. It is completely non-invasive.
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- Thread starter
- #7
I stand corrected. Somehow I had a nagging feeling that what I wrote wasn't quite right. I mistook the manual locking capability in lo for hi. My mistake. Nonetheless, the Pin 7 mod was completed and the sensor on the tcase remains plugged in.
I'm not sure if this helps you or not, but; In my 1999 105 the dash mounted CDL switch showed about 5 volts when I tested it during CDL trouble shooting.... but in that case the plug to the transfer case mounted CDL actuator was not seated properly. I had expected 12v at the CDL dash switch but did not re-test the switch after I 'fixed' the CDL by seating the actuator plug properly.
I have no idea if 80 series and 105s share similar CDL wiring so treat the above with caution.
- Thread starter
- #9
I think I have tracked the problem down to the IH1 harness. I have checked the plugs, grounds, & wiring in the left side kick panel and nothing seems amiss. However, there is also wiring in the circuit (all the wires that go to or come from the CDL actuator motor, actually) that goes through the IH1 connector that is listed in the FSM as "behind glove box". Seeing as how I believe I have checked the rest of the wires that may have been disturbed during my dash project, that's my next step. However, it is cold and snowy outside and I am lazy and unmotivated, so it might be a bit before I update this thread with my findings. Fingers crossed it's an unplugged or loose IH1 connector and it's obvious enough for me to easily find and repair it. Thanks for the help from those who contributed!
- Thread starter
- #11
I sometimes wonder if people don't update threads like this because the fix ends up being so embarrassingly simple. Well, for the sake of posterity and anyone else with a similar issue, here was my answer. I pulled the dash apart a little bit to trace wires, and I noticed the wire colors going to my CDL switch didn't match the FSM colors. Turns out that I switched the hazard and CDL switches. The plug fits fine in both switches (on a '91, at least). I switched the plugs back and everything works fine. Thanks for anyone who contributed to this thread. I imagine I would have figured it out eventually when I went to use my flashers and the CDL locked instead! Oh well. I am glad it was something so simple, but embarrassed for the same reason.
