2003 Silverado issue
 

Hey everyone, I have been an issue with my truck, a 2003 silverado ss. There are a few different things and I think some of them may be related.

1. Warning buzzer goes off and "service brakes soon" comes on the info center as well as illuminated ABS and (P) symbol. The warning lights will stay on until i shut the truck off

2. When the above is happening, the speedometer is erratic and the truck also shifts erratically, like its jumping between gears or it just revs high and shifting is delayed

3. Also, even when none of the above is happening and i engage the cruise control. The cruise will disengage or surge if I hit a bump

4. The left blinder doesn't work or also acts erratically, blinks super fast and then stops when you apply the brake. Yes, all the bulks have been verified on more than one occasion

I had taken it in once for this issue and they couldn't find anything definitive and didn't think the issues were related. Apparently they could nt find any fault codes either, which I found really odd.

Any ideas???

The 2003s had a TSB for the instrument clusters but I wouldn't think it would affect shifting. The other issues could be caused by a bad ground or BCM.

The ABS light can be caused by a failed airbag sensor but that should set a code. I replaced one of those on my 2003 2500 hd which was a pretty quick DIY job once identified.

If you don't have a code reader you can turn your android phone into one for about $20. Get a cheap bluetooth OBD II reader and the torque app and you are set. Then you can actively monitor and hopefully catch something.

Thanks for the tips. That diagnostic tool for your phone is pretty sweet!

Wow, I massacred the spelling in that post.. ha ha

Try the bcm (body control module) it controls all of the functions ur mentioning!

I just had to replace my turn signal flasher relay on my 2003 Sierra. I had a couple of the same issues. My turn signals wouldn't flash-they would just stay on constantly. I had the cruise control kick off as well. With the new relay I can hear it click when I step on the brake (I never noticed it with the old relay)-old one malfunctioning probably kicked off the cruise. My problems started when the weather recently got colder here. I would only have this problem for a few minutes in the morning when I first started driving when the truck was cold. After it warmed up for a few minutes the turn signals worked fine. It only took a few minutes to swap in a new relay that I picked up at Napa (LM455) for $30. The new relay is noisier than the old one which is pretty noticeable for me after driving the same truck for over 10 years now.