Sierra Z71 Service 4WD and Service Brake System

[rt646]

I got in my truck after work the other day and had all sorts of things light up.

ABS and Brake lights are on.
Service 4WD and Service Brake System messages.
Radio on but no sound.
4WD selector switch does not work and showing in Neutral. (But it is not in neutral)
The display for P N D etc...is blank.
Shifts hard between 1 and 2.

Wondering if anyone else has had this problem before?

2003 GMC Sierra Z71

 

[MROY16]

The Service 4WD is probably your switch no longer working. Replace the buttons, then disconnect the battery for 30mins and it should erase the 'Service 4WD' indication. Had that happen in mine recently, that fixed it.

For the ABS and park brake light, I'd suggest getting a look at the ABS Module, or the wheels speed sensors. My '99 has both lights on the WSS's are fine, the ABS Module is shot. Thats would probably also go with your 'Service Brake System' indication.

Not sure about the PRND321 being blank, but hard shifting could be a sign for a transmission service.

Radio with no sound, I'd suggest taking the radio out of the dash and checking all the connections make sure there aren't any loose wires hiding in the dash. If those are good, check the connections at the speakers. I'm not quite sure how to fix that issue as I've never had it before, but that's my thoughts on the subject.

 

[rt646]

Thanks for the reply MROY16.

Sounds like the suggestions you have are individualized to each service messages. My concern is why all of these issues happened at one time. So I was thinking that it may be where they all go somewhere in common. Like maybe the TCM or the PCM or something like that. I just don't know where there common points are.