Help: 4WD Help!!!

[03-GMC]

So my old mans trucks is doing some pretty weird stuff. His service 4wd light has been coming off and on so he checked all the fluids added a little to the front diff. Now he will be driving down the road and the 2HI light will start flashing as with the neutral light. After a second it will say its in neutral. I'm going to get a scanner to see if maybe it is throwing any codes tonight. He has the same truck as me but with no mods and his is a Chevy. Any ideas?

Thanks,
Derek

 

[03-GMC]

Bump.......

 

[Bluemax]

Probably a bad switch. They seem to go bad somewhat regularly. That and the shift encoder motor are the only things I know of that cause it to switch or flash once you're moving. The encoder motor will throw a code but sometimes the switch doesn't.

 

[8100 Power]

I would say switch. I've replaced a few.

 

[03-GMC]

Thanks guys i will try the switches first since it's the cheapest