Hey guys, I'm nick I'm new here. Searched through threads and saw nothing that helped my situation. I have a 2000 gmc jimmy which is giving me some issues. Was really hoping someone can point me in the right direction before just throwing money at it.

Ok here it goes. Vehicle has around 122k on it. When I bought it, only about 2k miles ago, it had a misfire but nothing terrible. Ran good, sometimes hard to start but once it started it ran decent. shifted good ect. Well out of the blue I started it and the abs light came on, once I started moving the parking brake light came on, speedometer wasn't working, and it wouldn't shift out of first gear. After like 30 seconds all the lights shut off, speedometer started working again and it shifted just fine. Now it's stuck in the lights on won't shift mode.

The only real back history I have is the guy who owned it before drove it through a flood and ever since then had multiple problems. Which I didn't find out until after I bought it. My thinking was the ecu became corroded and has now pooped out on me? But I'm not too sure. Anyone else ever see anything like this or know what I should look for? Please, any help or ideas would be appreciated. Thank you in advance and I hope I can help others sometime!

 

Yikes, a flood car. So many things to go wrong. You might as well start with the easy bits like unplugging and inspecting all of the electrical connections you can find for corrosion starting with the ECU and similar.

 

I was kinda afraid but expecting an answer like that, just wasn't too sure if there have been similar issues and someone knew a general place to start, but yes I'll start with the ecu, weather permitting I'll start this task tomorrow. Just looking for corrosion/moisture in the connections? I'm not too hot with electrical diagnosis.

 

Well I know I didn't get to all of the electrical connectors, I checked all 4 on the ecu, and many many more even if I didn't think it would have anything to do with the issue. I see absolutely no corrosion, they were all perfectly clean. Idk where to go from here. Anyone?

edit: I have gone through more connectors, checked all my frame grounds I could find (not sure how many there are) just to see if maybe a loose ground could be causing my problem. The battery ground was stupid loose, got it all tight but that didn't change a thing. Also just noticed, the parking brake light comes on shortly after the ABS light, even if I don't move the vehicle.

 

Dang. You could be seeing many independent things failing or one component that does multiple tasks. I would think there might be some advanced scan too that might help. Wish I could offer more but this is beyond me.

 

And I appreciate the input, I would appreciate any input even if it's a dead end. I'll check anything. At this point the only thing other than computer being fried that pops in my mind is the VSS but that would throw a CEL which i have no CEL. I was also told by a local here he bets it's the instrument cluster control module, which would mean changing the whole cluster which is $400 if I do it myself. what's anyone's input on that situation? I'm not a man made of money 😂

Edit: It has to be just one component. Both lights, speedometer and shifting issue started at the same time, stopped at the same time, and started back up at the same time.

 

A used instrument cluster is not that expensive if from a wrecking yard. I'm not familiar with the control module for it but I would think that would not be very expensive either.

 

well I was told the control module is part of the cluster and cannot be bought separate. This may have to be the route I go. I put it up on ramps today and checked more connectors from the bottom, none of which look corroded or like they had gotten wet. I wouldn't imagine a shift solenoid would turn my ABS and parking brake lights on or make my speedometer not work. Checked fuses, don't see any blown. Might just tinker around and figure out how to pull this instrument panel out and find me a close junkyard and I'm sure they have a jimmy or blazer (assuming they would be the same thing?)