Yet another CDL Issue (1 Viewer)

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Joined
Dec 8, 2016
Threads
3
Messages
19
Location
Martin, TN
Hey Mud, I've exhausted my troubleshooting skills on my CDL not engaging when it should.

I have a 1996 LX450 (no locking front or rear diff) with 144.5k miles, stock aside from adding the factory dash CDL switch.

When you turn the key to ACC and it does the bulb check, ABS lights up but the center diff lock light does not. I thought it was the bulb being burnt out, but when I shorted the connector for the T-case indicator switch, CDL and ABS lights were on. Pulled the switch, tested 5.4K ohms when closed, so it's bad. Whether in high or low gear, CDL switch engaged or not, the ABS and CDL light stayed lit up.

Thinking the diff was now stuck in locked position, I performed the pin-7 mod thinking I could use my CDL switch on the dash to lock and unlock the diff in high gear since with the pins shorted out at the switch connector the computer thinks I'm in low. Successfully removed Pin 7 and the ABS and CDL light were still stuck on no matter what position I had the transfer case in, CDL switch on or off, and any combination between them (still with indicator switch harness shorted with paper clip).

Fast forward to this morning, I got my new T-case position indicator switch, tested it closed @ 1.1 ohms and installed it..... still no CDL light on startup, when in 4-low, or when the CDL switch itself it pressed. In low gear I still don't even have the ABS light on.

Took it to a gravel lot, in out of low gear for some figure eights and still couldn't get it to engage or light up the CDL light.

For s***s and giggles I took it onto a paved parking lot, put her in 4-low, and made some tight turns and didn't have any driveline bind like I should have, nor while in 4 high with the CDL switch pressed.

Took it home, jacked up one tire to see if it would spin and it would go a few degrees before having a bunch of resistance, but still able to spin (in every combination of high, low, and switch on or off).

Prior to this, what I'm assuming is the CDL relay would chatter while at certain throttle positions around town and while at highway speeds. Today while driving, I realized pressing the CDL switch made this chattering stop.

P.S. I also don't get the "whirring" noise when the key is in accessory and I put it in low gear or press the CDL switch, just a relay click in the driver side kick pannel






Like I said I'm at a loss now, and need help getting pointed in the right direction of what to look at next. I figured the new indicator switch would have fixed my issue but it did not. I'm going to assume the CDL relay, actuator, or something internal to the transfer case at this point, but I'm hoping it something stupid I just overlooked.
 
Did you check the diff fuse on the fuse box left of the steering wheel? I think its 20 or 30 amps.
 
Yes, all fuses are good, forgot to mention that.

Am I correct in assuming that with the pin-7 mod completed and the indicator switch shorted, pressing my CDL switch should have turned the lights off?
 
Went out again, Shorted the position indicator switch so the ABS and CDL light were illuminated, drove and reversed a few feet and jacked up the wheel to see if it was in fact locked, and again it just had some resistance after a few degrees but would still spin. So is there a way to test the actuator without removing it from the car?
 
With ignition on, engine not running, do you hear the CDL relay click in the left side kick panel? If no click, possibly dud relay.
If it clicks, and you don't hear the actuator, you either have bad wiring, or a bad actuator.

If you can pull the harness connector of the actuator, check to see if you have 12volts at the plug.
Should be five wires from memory, 2 are the CDL position indicator switch, the other three are ground, 12v motor for licking, 12v motor for unlock
 
With the harness disconnected from the actuator, and CDL button pressed, you should have 12v at the plug to lock it. Release the CDL button, and you should see 12v on another wire for unlock.
 
Yes I hear the relay click in the driver side kick panel, thanks for the tip on testing actuator, will get back out there tonight after steak and a few more #6's
 
@agp35 Did you ever chase this down? Looks like CDL actuator motor.
 

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