So, who knows Autotrac like the back of their hand?

[sandrock]

Yeah, it's gonna be one of THOSE posts...

Patient: 99 Tahoe LT, 230k on the ticker.

Symptom 1: Auto 4wd does not engage. 2hi, 4hi and 4low work as they should.

Symptom 2: 4hi lamp on switch stays lit regardless of whatever mode is selected. If 2hi is selected, 2hi is lit, 4hi remains lit, and so on. If I select 4hi, it dims a little but remains on. Disassembled switch, reflowed all solder points (and added LEDs for backlighting along with limit resistor), same result. New switch, same result.

I have a 100.00 deductable powertrain warranty that I got when I bought the truck, so if it's the transfer case I'm covered. Anything electrical like the actuators and encoders I'm on my own, so I need to know if anyone else has had issues like this, or even what I can rule out.

Thanks guys!

 

[Jounier11]

your covered by a 100.00 bucks a new transfer case cost about 500.00 and up depending what brand you buy.

 

[Andrew99Tahoe]

Yeah, it's gonna be one of THOSE posts...

Patient: 99 Tahoe LT, 230k on the ticker.

Symptom 1: Auto 4wd does not engage. 2hi, 4hi and 4low work as they should.

Symptom 2: 4hi lamp on switch stays lit regardless of whatever mode is selected. If 2hi is selected, 2hi is lit, 4hi remains lit, and so on. If I select 4hi, it dims a little but remains on. Disassembled switch, reflowed all solder points (and added LEDs for backlighting along with limit resistor), same result. New switch, same result.

I have a 100.00 deductable powertrain warranty that I got when I bought the truck, so if it's the transfer case I'm covered. Anything electrical like the actuators and encoders I'm on my own, so I need to know if anyone else has had issues like this, or even what I can rule out.

Thanks guys!

It could be anything from the switch on the dash from the switch on the dash down to the encoder motor on the tcase.

 

[lesterl]

He tried a new switch. Have you reset the PCM?

 

[sandrock]

Yup, tried that. Reseated all the connectors too at the front actuator and the trans case encoder.

 

[Jounier11]

Honestly sounds to me like the actuator just needs to be replaced about 50.00 off e-bay good luck and :welcome:

 

[sandrock]

Hey thanks! The actuator...I imagine you're talking about the front axle one? Does it have a feedback circuit that actually confirms it's in 4wd? And are there seperate confirmations for 4hi and 4lo?