TC/CDL + ABS light illuminated (but TC/CDL not locked)

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Oct 22, 2018
San Diego, CA
Hiya Mudders!

I'm a bit stumped (and searched through the forums for any clues, but didn't find any related issues). My 1997 80 recently developed a strange behavior w/ the TC/CDL and ABS dashboard indicators. The truck has the pin-7 mod, for reference.
  • After a long highway drive OR to SF, CA) the TC/CDL+ABS (indicating TC was locked) illuminated. There was no mechanical locking going on. The TC was unlocked.
  • When I hit the TC/CDL lock button, I can hear the relay clicking, and the TC does lock. When I use the button to "unlock" the lights turn off for a second, the TC unlocks, and then the lights turn back on (even though it's unlocked, and the button is not pushed)
  • When driving, the lights might turn off.
  • Also, the TC/CDL light might flicker and turn off, but the ABS light might stay illuminated
  • Sometimes, when I park the truck, the lights will be off, and then when I restart, both will be on
  • There is nothing wrong with the driveability - everything drives normally
I checked, and there haven't been any rats eating my wires....The TC indicator switch was also replaced recently, and everything was working fine afterwards

Could the ABS sensors be causing this issue?

Or, is it possible that a bunch of Range Rovers parked near the 80, and the electrical gremlins molested my poor truck?:rofl:

Thanks for any help and thoughts!
Disconnect switch on xfer case. Does light go out?
Could be that simple😉, bad switch. Just because it was replaced doesn’t mean it’s good!
If it does not go out start moving the harness around to see if you can make it go out.

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