Service 4WD message

[foghorn23]

Well I know it's a common problem on these trucks, but I got the "Service 4WD" message on the DIC as I was driving home this afternoon. Also the lights in the switch itself are not burning.

 

Does that sound like the symptoms of a bad switch? Also, I assume if it's just the switch there's no problem with driving it????

 

Got appointment with dealer tomorrow @ 2:00. No real sweat as it's a warranty issue, just wanted to see if this sounded like the same problem to those of you who've seen a bad 4WD switch.

 

vroten

[71GMC_3/4T]

Yes, it sounds like a bad switch. Mine did the same thing. No lights, no backlights, no worky. The fact that the backlights AND the switch indicators were out tells me it was a faulty ground.

 

I wouldn't know if it will screw something up by being bad or not.

When mine flipped out, I shut it off, pushed all the buttons a bunch of times and turned it back on and it worked. The next day, it worked fine.

 

I pulled it on the following weekend and reflowed all the solder on the connector pins and it hasn't failed yet (~2 months). Yes, it probably would have been fixed under warranty, but now I know the solder is right and shouldn't fail ever again. A new switch seemed like a problem waiting to happen again.

[bobcat5544]

IT CAN BE TO THINGS EATHER THE SWICH OR INSIDE THE INCODER MOTOR MOD ON THE TRANFER CASE, BUT BEFORE REPLACEING EATHER ONE

 

GM HAS A TECH SERVICE BULLETIN ABOUT THIS PROBLEM. WHICH TCCM NEED TO BE REPROGRAMED

[foghorn23]

Like 71GMC_3/4T said: After I let the truck set for about 1/2 hour when I re-cranked and everything was back to normal. Wondering about the TCCM (?????) reprogram. Is there a bulletin # on that?

 

thanks

vroten

[foghorn23]

I believe Bobcatt5544 was right. Seems if it were a switch the problem wouldn't be intermittant The dealer did a reprogram on the TCCM.....seems to have fixed the problem...... hopefully. Thanks for the info Bobcatt

 

vroten

[roden001]

See my post in the following thread for the service bulletin:

 

http://www.gm-trucks.com/forums/index.php?...57entry307557

 

I solved my problem by following the instructions (pulled an underhood fuse, waited 30 seconds, replaced the fuse), and have not had the message return for 3 months now.

 

Good luck.

[71GMC_3/4T]

Roden,

I read the TSB verbage you posted the link to.

I'm wondering if you need to do this with the key on or off, or does it matter?

Thanks,

'71

[bobcat5544]

no problem if you have any more problem or questions i have some of the most updataed info on all gm cars and trucks

[roden001]

Roden,

I read the TSB verbage you posted the link to.

I'm wondering if you need to do this with the key on or off, or does it matter?

Thanks,

'71

 

<{POST_SNAPBACK}>

 

 

 

I'm pretty sure I did it with the engine running. I'll add that I never had the TCM thingy reprogrammed. I figured I'd do that if the thing kept acting up. So far so good.

BTW, sorry about the late reply--I'VE BEEN AT THE BEACH!!!

[71GMC_3/4T]

Hey Thanks for the info!

Hope you had a great time on the beach!