My 4wd dash switch is not working so I have no clue if my 4wd works? And with upcoming winter I'd like to get this issue resolved.. wat can I do to get the dash switch to work again? Wat fuses should I check first

 

What year, make, model & engine? Does the 4WD dash switch have 3 buttons or 4? Do the lights in the buttons come on when you turn the ignition to the RUN position?

 

Sorry always forget to post that info...
It's a 2001 blazer 4.3l with 4 button switch 236 tcase..
And yes the lights flash for a second when I turn the truck on.. then go off and stay off

 

The flashing lights are indicating a trouble code. How many times do they flash?

 

First check fuses.
Next pull the passenger foot trim panel off and remove the connector from the TCCM and check the contacts; clean as needed.
Then I would remove the 4x4 switch from the dash, disconnect connector. Take to bench and separate the two housings so as to expose the circuit board. Reflow all the solder connections, re-install.
Hopefully this cures the problem. If not, then is the encoder motor making any noise when the 4HI button is pressed? Is the vacuum actuator under the battery moving when the 4HI button is pressed? Could be the TCCM is just shot.

 

They don't necessarily flash. . Just turn on then off for a quick second..

Which fuses do I check for the 4wd system?.. only one I seen in the fuse panel in the truck was the 4wd fuse and that was good.. are there any other fuses to check?

Also I checked the connections on the tccm and the dash switch itself and none needed cleaning.. i also swapped tccm with a known good one and a new dash switch..

I also checked the vacuum actuator under the battery and the diaphragm seems good and a the cable doesn't seen frozen but I can't get vacuum to the actuator under the battery because I get no response from the dash switch

 

The 2HI lite only illuminates for a second or so when the key is turned to ON and then goes dark, is this correct?

Swapping-in known good parts results in no difference, is this correct?

Take another look at the electrical connectors for both TCCM and 4wd switch; possibly there is a contact that has pushed-in. Give a little tug on each wire at each connector to ensure that each contact is locked into place.

All I can think of at the moment.

 

My 2 hi light used to stay illuminated the whole time..unless in 4wd..
Yes known good parts made no difference..
I'll have to double check all the wires again today but I'm pretty sure they were all good last time I checked them.

Which fuse exactly is it for the dash switch? ?

 

I had the same problem there is a module in the passenger side kick panel for the transfer case, you have to take the plug going into that module and put dielectric grease in that connector.... after i did that i stopped losing power to the switch. The connections get tarnished and lose conductivity.

 

I'll try that too I guess..

Trying to get this fixed asap as they are calling for snow later this week