I am (was) the VERY happy owner of an H3.

However, back in Nov., I started getting the dreaded "Reduced Power" message on the dash, and the vehicle would go limp (or not start at all).

I've watched a million videos on this on YT, taken in to a mechanic who specializes in Hummers, and bottom line: there's a short SOMEWHERE... but we can't find it.

We've replaced the obvious stuff... no luck.

At this point he's telling me "its junk... cannot be fixed at a reasonable price".

Ugh... any ideas... or am I simply screwed?

 

 

mine was a throttle body, but codes would be great

 

Wrench told me that he cant get a code: he's losing communication with the PCM and the ECM.

It wont do ANYTHING, turn over, start, etc.

I'm at a complete loss and I've already paid him $1400.

He worked for the local Chevy dealership and came very highly recommended by other mechanics locally: he handled the dealership's electrical repair issues and has loads of experience with H3's.

Any advice would be helpful...

 

unless your going to tackle the situation yourself. nothing is going to happen. the current mechanic has basically thrown in the towel.... or he likes the vehicle and figures you will just leave / give it to him. i personally would first start with the battery and it's terminals then move on to chassis grounds. then check to see if there is voltage present at the ODB2 connector. then keep whittling away to see why there is no communications. maybe unplug the BCM and see if the others come back online or vise versa disconnect the PCM and see if they come back on. Harnesses can go bad as well as the fuse box if it has the green oxidation on the terminals / fuse terminals.

if it has been at other shops i would also make sure the fuse box harnesses are properly seated because they might not be seated correctly if they have been disturbed

 

Are you still using the Crappy Azzed Defective OEM Battery Terminal Connectors? If so, they need to be hacked off and replaced with a quality aftermarket set like Stingers or your favorite brand. That alone can cause your issues.

Do you have a Sunroof? If so, has the passenger side floor been wet........ have you done the Sunroof Drain Fix?

The "dealership" is the last place to take anything out of warranty for repair and diagnosis. Working on an H3 is like working on most any other GM truck, no rocket science needed.

 

I an almost certainly tell you that guy just doesn't want to work on it. The first thing I would do is go to an auto parts store and ask them to try and scan it before you do anything. There isn't really a whole lot special going on with obdII wiring, If theres an issue, its gonna be a shorted/cut wire somewhere or a bad module. Either way, its going to be fixable.

 

I appreciate all the ideas: I have to decide to either junk it... or find another wrench.

Based on the responses I'm leaning toward finding another wrench... so any specific ideas that I can pass on to the new guy are very much appreciated.

 

I had cleaned the batt terminals a few months ago as I originally thought that might be the problem; they're as clean as a whistle.

And thanks for all the ideas so far!

 

I had leakage on the floor, but I adjusted the sunroof and poof! No more leakage.

I will see if I can get terminals replaced.

Thanks!