4wd lock, HELP!!

blueskittle89 · May 4, 2013

I have a 2003 GMC Sierra 1500hd SLE with 95,xxx miles. I starded having an issue where my truck would shift into 4hi by itself after about 20-30 minutes of driving. I used to be able to just put it back into 2hi. Then it became more finicky and I had to shift to AUTO 4wd, then into 2hi. Now it rarely lets me shift into 2hi, and never into 4lo. I am a first time truck owner and have only owned this truck for 6 months.

I think it may just be an electrical issue because the truck started having some random electrical issues. Whenever I use my turn signals my left signal indicator stays illuminated for 5-10 seconds. And when I turn on my cabin light it flickers sometimes. I also have an issue where whenever I go over 70 on the highway my CEL flashes.

I'm a broke college student and I refust to take it to the stealership until I have done everything I can to fix the problem myself. Any insight would be greatly appreciated.

Thank you

j-ten-ner · May 4, 2013

Most electrical issues are caused by a bad ground or bad/lose/rusted connections.

Check your battery and ground connections first.

Remove the screws and bolts holding the cables, clean them and reconnect them.

Use dielectric grease.

so long

j-ten-ner

Badass69 · May 4, 2013

Sounds like a multitude of unrelated problems. The 4X4 thing is basically one of two things. The dash buttons are going bad or the encoder motor in the t-case itself. The encoder motor is what I usually go after especially if its original. They leak water and corrode themselves to death inside among other issues.

Could be a bad ground..... Flashing CEL is usually a misfire indication. If you scan the pcm for codes you may have the PO300 random misfire code. Too many variables to accurately tell. Same goes for the dash. Anything from the cluster, a bad ground or even the signal flasher. Like some guys reply..... we are just guessing without the truck in front of us.

oubobcat · May 8, 2013

You could try replacing the switch on the dash. amazon has them for $55. Did service 4wd display on the DIC?

BlackZ71Silverado · May 8, 2013

I have a 2003 GMC Sierra 1500hd SLE with 95,xxx miles. I starded having an issue where my truck would shift into 4hi by itself after about 20-30 minutes of driving. I used to be able to just put it back into 2hi. Then it became more finicky and I had to shift to AUTO 4wd, then into 2hi. Now it rarely lets me shift into 2hi, and never into 4lo. I am a first time truck owner and have only owned this truck for 6 months.

I think it may just be an electrical issue because the truck started having some random electrical issues. Whenever I use my turn signals my left signal indicator stays illuminated for 5-10 seconds. And when I turn on my cabin light it flickers sometimes. I also have an issue where whenever I go over 70 on the highway my CEL flashes.

I'm a broke college student and I refust to take it to the stealership until I have done everything I can to fix the problem myself. Any insight would be greatly appreciated.

Thank you

The best option you have with that many different problems is to take it to the dealership where you bought it. Far to many thing to be throwing money at to try and fix on your own. Electrical problems suck, take it in and have them look at it.

tkat1000 · May 8, 2013

put a dash switch in it. gm's been using the same faulty switch since 98

dblacktruck · November 5, 2013

I just purchased a 2014 Silverado Truck. When I made a left turn it would make a real loud noise. So then I made another turn with in 1/2 mile and the truck acted like it didn't want to go in gear. Dealership says it is a Transfer Case. For a new truck parts have not been manufactured yet. Haven't have the truck but a few months. Suggestions please? Lemon Law?