4 Wheel Drive Diagnostics

[BobGTahoe]

Thanks. We just got it working thanks to your last post. That provided enough information that we figured it out.

Thanks again (I guess the force was with us!).

 

[scrnchr]

Does anyone have a similar 4WD Diagnostics guide for a 2004 Tahoe?

My 2004 Tahoe has the Auto setting, so the posted diagnostics apparently don't apply. It looks to me like my data link connector doesn't have a pin in slot 13--just the plastic housing.

 

[scrnchr]

I took my dash 4WD switch apart, but it was in good shape. I've read that by 2004 the switches weren't usually the problem. Ended up replacing the transfer case encoder motor. Kind of a pain to do. It fixed the problem, though.

 

[lesterl]

Good to know....

 

[kellygr83]

My problem is my service 4 wheel drive light is on its a 99 chevy tahoe and my four wheel drive doesnt work you can hear evrything clicking over but it wont work i do not know much about the problem but neither does the shops i take it too they just keep telling me to replace the transfer case but i have gotten it to work by tinkering with it im thinking it may be the encoder motor but know part store knows which one my vehicle takes

 

[Jounier11]

could be a lot of things maybe even the switch, Good Luck

 

[Jounier11]

I get service 4wd light to but my button switch on the dash has gone to crap since i go off roading every sunday the actual plastic has broken so at night i see the light bulbs lit up also the orange indicator doesn light up on 2wd and 4hi its not that its not changing gears but the switch just needs to be replaced checked at the dealer they want $110 for a new one went to gmpartsdirect $56 out the door with free shipping

 

[Char78]

So what are the instructions to get 4wd service light to blink without a scanner? I can't open the doc. Thanks in advance

 

[sportblazer350]

Look above the actuator on the diff to see if there is a 2 pin connector. This is what is used on the thermal actuator type to determine if the diff is actually engaged or not.

I think that since your truck is a 97 it should have the motor type actuator. I believe that 96 was the last year that the thermal actuator was used on 1/2 ton trucks but I can't state that as a fact, someone else may know.

The actuator is available at an auto parts for less than $100.

in 2011 a dealership replaced my actuator with a new 2011 model actuator and new pigtail wiring harness which works much better than the original thermal unit. Also had a switch under the 4wd shifter replaced. 1994 Blazer 350 v8

 

[mountainman-7]

loulblades, your Chevy 4wd would't open up. Can it be opened up? Thank you!

 

[Dwells1966]

1997 tahoe 4wd

I have 1997 tahoe 4wd acting up. Found a switch top left side of transfer case was corroded up. Replaced switch and conector. It fixed problem