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Intermittent lights on 4wd selector switch, service 4wd message..

TurboTravis

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TurboTravis New Member

TurboTravis

Posted
Posted

New guy here. Hello everyone!

 

Long story short...2005 5.3 Crew Cab Silverado LT. About 2 months ago, I was getting the 'service 4wd' message. Did some research online, and replaced the switch on the dash. All was well for about a month, and then the message was coming back.

 

Discussed it with a GM tech and decided to replace the encoder motor. I had to wait a couple weeks before I got to it. In the meantime, the truck started doing different things every time you started it. Sometimes I'm getting the 'service 4wd' right away, sometimes the 4wd works, sometimes there are no lights illuminated on the selector switch, sometimes just the red one is..totally random.

 

I cleaned the grounds on the chassis under the driver door today, and replaced the terminals. Have not driven it much but it's still doing random things for sure.

 

What's next guys? Just change the encoder motor and the transfer case module at the same time? Or is this problem definitely one or the other?

 

Thanks in advance for the help.

TurboTravis New Member

TurboTravis

Posted
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Well, so far since I cleaned and reterminated the grounds, the lights are working all the time so far. Just drove it-4wd worked for a bit, then got 'service 4wd' message.

06pirate Enthusiast

06pirate

Posted
Posted

My 2006 Sierra SLT was doing pretty much the same thing and I also replaced the dashboard switch, which cured nothing. My OBD2 scanner showed no codes. One day it shifted into 4WL by itself and stuck there. Towed it to the dealer and the Xfer case was destroyed because the oil pump had worn a hole in it and pumped all the oil out. Nothing left worth rebuilding. Check your Xfer case oil level etc., on the chance that it may be low and if it is, maybe you can save it before it digests itself.

 

Now I know about the "case saver" device, but doubt I'll ever get a chance to pull the unit out and install it.

SpartanAutoworx Enthusiast

SpartanAutoworx

Posted
Posted

Does it start in 4low? If so get the TCCM Module re Flashed. Also what codes you getting when svc 4wd comes up

bulldog52 Enthusiast

bulldog52

Posted
Posted

I had the exact same problem with my 06 VMax crew cab. Service 4wd would flash intermittently, 4wd lights would sometimes go out, and sometimes it would change the throttle program thinking it was in 4 low. Removed the shift motor from the transfer case and replaced the shift position sensor.

 

Sent from my XT1565 using Tapatalk

  • 2 months later...
Tedlafond New Member

Tedlafond

Posted
Posted

OK I have a strange fix for my 2003 envoy..what's the temperature? Anytime the outside temp falls below 55 degrees I have issues with engaging 4wd...the TCCM in my vehicle is located under the dash drivers side...I decided to experiment..I started my vehicle,turned the heat on to the floor full blast for about 20 minutes.. got it nice and hot...I don't know if the TCCM is just cold or what not,but ever since I started heating up under the dash,i never had a problem...I never have any problem with it,if it is warm outside...hope this helps and it's a free fix if it does

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