electronic 4x4 question before the snow gets here.

[97blueyuk]

ok its a 97 yukon with electronic push button 4x4. when i test drove the truck it felt like it was in 4wd when turning. I pushed the button to 2wd did the reverse thing and nothing. I got back to the guys house laid under it and confirmed the front shaft was spinning. We got it disengaged.

The previous owner told me it worked fine but only when the lights on the buttons where lit and that was not all the time.

Winter can get pretty bad around here from time to time and I want my 4x4 to work when it is needed not when it feels like it. I have been noticing recently the lights being lit and not lit.

My question is how to test and repair any issues with this electronic 4wd system. Right now it is not my primary veh and have some time off from work to put into getting this taken care of. Any help is greatly appreciated.

 

[BRUTUS_T_HOG]

The most common cause is a bad switch. They don't have many intermittent problems other than that. Is possible that from lack of use the encoder switch on the shift motor is gummed up and can't keep track of what gear it is in.

You might try cycling the control switches multiple times and see if they work off and on. I've gotten them to act up by pressing extra ******* the buttons. Sometimes one might be stuck down.

 

[97blueyuk]

ill pull the switches and try to clean them and see if that does anything hopefully it is something simple like that any other ideas??

 

[97blueyuk]

okay so i am back to this project. as of right now there are no 2whl 4hi or 4lo lights on, i cycled the buttons a bunch of times for about 5 mins. The 2 fuses are good. I pulled them for a few mins for any resetting that could maybe occur. Before I crawl under this thing with my tools anything else to check?

 

[SunlitComet]

grab a multimeter and actually probe the connectors on it to see if the tccm is providing the voltage to the switch buttons and lights as it should.

 

[97blueyuk]

okay lemme try n get this right, you are saying to pull the selector switch on dash and check the voltage at that harness is that correct? is there any wiring under the truck to check while im at it?

 

[kcb37]

Have another option maybe.
My mom's 95 S10 blazer. (4wd works fine however) lights in the switch were burnt out. $5 dollars they all light up now.
Sure you have more issues, I would also guess the buttons. (whole switch)
But if you have lights burnt out.

 

[97blueyuk]

Changed the switch on the dash. Cleaned up the connection tested good. I grabbed a switch from the j/y this morning just incase. The old switch works fine when hanging out of dash but now when in dash. I switched the switches and it seems fine now. Will have to keep an eye on it but I dont feel like I will be stranded in the snow now

 

[2DR4EVR]

What does it mean when the light blinks? My 4HI Blinks....doesnt feel like its engaging. 4LO now blinks but I know its dropped in. It used to not blink.

I just had the actuator switch replaced.....didn't seem to solve anything.