4 wheel drive won't engage

gjgeyer · September 6, 2014

I have a 2003 2500HD Silverado...the 4 wheel drive won't engage. I do not have auto 4wd.

when I press the button to switch to 4wd, the light just blinks and then returns to a solid light on 2wd.

I can here a click after I press the button, but I cannot hear the shift motor running. My question is, is there a way to decipher whether my problem is the shift actuator, or the shift motor. I think it is the shift motor, but not sure

Thanks in advance any help is appreciated.

gmtech4 · September 6, 2014

You need to get it scanned for codes with a scanner able to read TCCM codes ,

Don't guess

gjgeyer · September 7, 2014

Thanks Rob, I'll get that done today

gjgeyer · September 7, 2014

Ok, got it scanned today, no TCCM codes were found.

any Ideas where to go from there?

gmtech4 · September 8, 2014

There is a code , who scanned it and with what ?

gjgeyer · September 8, 2014

I went to the mechanic that works on the vehicles at work, I don't know what kind of scanner he used, he was baffled as well. He said it's possible that if there are no "dummy lights" or anything reading on the dic it won't store a code? I'm taking it tomorrow to an independent mechanic to run codes.

kdeerman · September 10, 2014

How do I tell if my scanner reads TCCM codes? I just bought an

Equus / Innova 3130 / 1303 CAN OBD 2 Pro Global Scan Tool

Thanks

kdeerman · September 12, 2014

Can I swap the TCCM from my 2004 Suburban to my 2006 Sierra and see if that is my problem? Part numbers are the same, just wondering if programming or something else is different. No lights on switch and no 4WD. Have swapped switch already.

Thanks.

gmtech4 · September 13, 2014

why did you start another thread ?

gjgeyer · September 27, 2014

I didn't start a new thread, maybe you are talking to kdeerman?

Anyhow, I finally got the truck re-scanned. No codes found, however, was able to test actuator and tested good through scan tool (snap on). I tested ohms on the selector switch....2H tested at 1680 ohms, 4H, 860, and 4L showed only one ohm. I'm thinking selector switch, what do you think Rob?

gmtech4 · September 27, 2014

Sure why not,

SouthernSilveradoGuy85 · September 28, 2014

Same thing happened on my 98. It was just the selector switch in the dash.

gjgeyer · September 30, 2014

ok, tried new selector switch...no go. I'll be able to take it back for a refund. Narrows it down to two..shift motor or TCCM. I'm thinking if the TCCM is bad perhaps that is the reason it's not throwing codes?