Hello,
I'm a longtime, non member that has used this forum many times researching issues related to the H3 over the past 2 years. My girlfriend has a 2006 Hummer H3, she rarely took it in for service unless there was a major problem. This caused a big argument about "taking care of sh..tuff." Long story, now the Hummer is my responsibility.

2006 Hummer H3
100k Miles

Recent Maintenance:
-Changed Plugs
-Changed Oil
-Changed Air Filter
-Cleaned TB

To Do:
Trans Flush/Fill
P.Steering/Differentials/Brake flush/fill
Brakes/Rotors


Latest Issue:
Rear Tail Lights(Not the Top), Rear Hazards and Rear Turn Signals are out. Fronts work fine. Researched issue on this forum, inspected rear trailer harness for damage, wear, etc. Found nothing. Re-read the forum threads. Looked again for shorted or any frayed wires. Found nothing. The trailer harness was actually wrapped up pretty well, almost looked like it had been post purchase, possibly during a servicing, because of the crappy electrical tape job on the rugged looking cable sleeving.

With her 2 year inspection coming up next month, I bit the bullet and took it to the local Lou Fusz/Chevy dealership near St. Louis, MO. After almost 2 days with the vehicle, I get a call telling me they found the issue: Bad harnesses between the BCM and the Rear Brake/Turn modules. Don't quote me on the exact verbage, but I'm sure you get this jest. They don't have the part in stock so they will need to hold the truck, as its in pieces, until Monday when it arrives. The vehicle has been there since Wednesday night. Cost: $407 for parts/labor.

Issues experienced thus far:

1. Driver window/All Power locks won't work, no signs of any mechanical or electrical movements. Resolved from research on this forum. Combination of touching Pos/Neg cables together for 15 minutes and removing Window/Lock controller from Driver Door and setting on heating vent in house for 15 minutes. This was after checking all the usual suspect, fuses, voltages, etc. Issue happened after battery drained below crank levels.

2. Check Engine Light - P0302 - Misfire on Cyclinder 2. Swapped Coil #2 with Coil #3, swapped spark plug #2 with #3. P0302 misfire again! The CEL comes on after the engine has warmed up. I changed the spark plugs with the OEM recommended/pre-gapped about 2 months ago.
GM/Chevy Mechanic response after brief investigation: Possible Cyclinder Head issue.

3. AC/Heater Fan Blower harness/resistor melted causing the fan to short out and stop working if bumped or kicked. This is the famous harness located directly under the glove box on the passenger side by the kick panel. Decided to hold off on that for now, I remember reading How To's on this just didn't have time to get into it.
The GM/Chevy dealership wanted $200+ to replace.

4. TPM SRV message about Tire Pressure monitors. Only seems to happen in sub freezing temps. Hummer stays garaged but it's been ridiculous cold as I'm sure some of you already know.

5. AC/Heater Fan Speed, Temperature and Mode selection lights don't work. Very hard to see at night. Haven't done a lot of research on this one yet.

So thats it, thats my synapsis of all the headaches I've inherited with this H3. On a side note, I've never driven a 4x4 before as I've always been a sports car guy. She made the mistake of letting me drive it alone when it snowed very heavily. These things are beast, I tried my best to get this thing stuck and it wouldn't have it.