Another CDL question

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Dec 9, 2020
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I did quite a bit of reading on here but could not find a thread that helped me identify what is happening with my CDL. I have a 1997 that is triple locked. I’ve been doing a lot of work on the vehicle lately and I replaced the CDL switch with a new one from rock auto because the CDl light was not indicating on the dash (and I didn’t hear the actuator engaging) with the old switch. I didn’t have any luck with the new switch, so I tried the paperclip trick. Sure enough, the light on the dash lit up. So, I’ve been been shifting into 4L whenever I get the chance. Tonight, I finally got the CDL dash light to appear, but I didn’t hear the actuator engage. I heard the relay clicking though. When the CDL light was on, my front and rear locker lights would only blink when I tried to engage them. Finally, the CDL light would only turn on when the 4L gear shifter was in a very specific spot when shifted in 4L. I had to move the shifter around a bit in order to find the sweet spot. Does this sound like a bad actuator, a bad switch, or a bad something else? Thanks for the help.
 
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I replaced the CDL switch
Which one? There are three: 1) CDL indicator switch, 2) low range position switch, 3) neutral position switch.

The transfer case shifter needing to be in a specific spot sounds like a bad low range position switch to me.
 
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Transfer Position Switches Top View.jpg
 
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It sounds like a new low range position switch is in order. I have a follow up question on this though: shouldn’t the center differential lock when I am able to get the low range shifter into the right spot so the dash light appears? It seems to me that even if I need a new low range switch, if I can get the dash light to appear with this switch and I hear the relay clicking, the center differential should still lock.
 
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shouldn’t the center differential lock when I am able to get the low range shifter into the right spot so the dash light appears?

Yes, unless someone has done the pin 7 mod.

It seems to me that even if I need a new low range switch, if I can get the dash light to appear with this switch and I hear the relay clicking, the center differential should still lock.

I believe it's accurate to say that if you hear the CDL relay click, you should *always* hear the CDL motor run. With the engine off, that is, since it's not very loud. I don't believe there's any additional logic in that circuit.

Based upon what you wrote earlier:

I finally got the CDL dash light to appear, but I didn’t hear the actuator engage. I heard the relay clicking though. When the CDL light was on

The CDL light circuit is "dumb". All it knows is that the CDL has moved into the locked position, which pushes on the spring-loaded ball at the end of the switch. If the light is on, your CDL is locked *or* somehow the switch has failed in the "on" state (I don't think I've ever heard of the t-case switches failing in the "on" state). The CDL motor is not very loud, it's just a whirring noise.

@george_tlc wrote about his torture techniques (beating and electric shock) for rehabilitating the t-case switches a long time ago:

By the way, if you didn't know, you can pull the upper dash panel and move your hazard switch to the unused CDL plug. Then you can cycle the CDL directly for testing.
 

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