Hi! Long time lurker, first time poster here. Apologies if this post is in the wrong section. I've done a few searches and didn't see anyone who's experienced this same phenomenon.

I've got a 2000 Blazer ZR2 with the NP 236 transfer case and 4-button dash switch.

As the title states, my issue (or maybe quirk?) is that when 2 HI is selected, both the 2 HI and AUTO 4WD lights on the switch are lit. As I understand, only one light should be on for any given selection on the switch, correct?

I *think* AUTO 4WD stays lit when selecting 4 HI and 4 LO as well, but I'd have to double check and report back. I have the vacuum line to the diaphragm/cable to the front diff disconnected/capped off for now because I have no use for it other than during winter here in Central IL.

I work at a parts store and tried swapping the switch with a new Dorman unit and it made no difference.

also cleaned the connections to the TCCM behind the passenger kick panel and that made no difference in the lights on the dash switch.

ANYWAY, I'll get on with it. Thanks for bearing with me. Could a faulty transfer case encoder motor be the culprit here? Could the encoder motor be stuck between the AUTO and 2 HI position on the transfer case? Any ideas/input would be appreciated!

 

if the encoder motor has an issue it will set a Check 4WD light. sounds more like the TCCM was shorted out anyways or the dorman unit was junk also (and, i would not be surprised in the slightest. given personal experience with dorman parts, dont ask me about hinges)