My 2006 h3 is suddenly developing electrical failure: it will drive perfect - I park, come out next day, no power. Key will not release from ignition. Will start when battery jumped. Body control modular replaced and new battery. Mechanic suggested some type of "parasitic drain on system." Anyone else experience a similar problem?

 

Three things to check.

1) Why was the BCM replaced? Do you have a sun roof, and has it ever leaked? When you do not do the clogged sun roof drain fix, water will build up, leak above the headliner and down the passenger side A pillar causing the BCM to get wet and short.

If this happened to you, then replacing the BCM without fixing the problem will just repeat that problem.

Search fix for clogged sunroof drains. Link https://www.hummerforums.com/forum/h...n-tubes-28548/

2) Do you still have the crappy azzed OEM battery terminal connectors? If you do, they are complete chit and can cause all sorts of electrical Gremlins, which usually start when somebody replaces/disconnects/jumps the battery and either over-tightens them or causes them to become loose. Search that out as well, first mod everybody should do to any H3, replace the OEM battery terminal connectors with a quality aftermarket set like Stingers or your favorite brand. Cheap insurance to rule out future Gremlins.

3) Open the rear door, look under the chassis above the bumper to see if the wiring harness to the license plate light or trailer plug are rubbing anything through the wire insulation and causing a ground. Happened to mine and a bunch of others.

4) Start looking for the source of a draw.... lots of ways to do that, others will chime in, but always do the easy stuff first (1, 2 & 3 above).

 

Forgot my manners.... Welcome to HF.

This has been MOVED because like it says in the FAQ section.... DO NOT POST in the FAQ section just because you thought up a question. https://www.hummerforums.com/forum/h...section-19461/

 

My h3 does not have a sun roof. I do have the original battery terminal connectors and, the last time the battery was replaced was 2014.

 

There are basically 2 ways an H3 BCM gets wet, by the sunroof, or a flood. It is not unusual for either. The nearly exclusive reason to replace the BCM is water intrusion, but it is an electrical man made part and there are surely bad ones out there

I want to make sure I understand. Did you replace the battery in 2014 and again just recently? If not, it is entirely possible you have a bad cell in the battery.

Did you replace the battery or have somebody else do that?

You are lucky the stock battery terminal connectors worked that long.

Seriously, search it out, the OEM battery terminal connectors are a known problem.

Good luck.

 

The dealership replaced the battery in 2014. 28 March, 2016, when the truck didn't start, I had AAA jump start it and, I drovre it for several hours before turning truck off. On 29 March, truck would not start and, I had truck towed to Anderson dealership, where I had purchased truck. They kept the truck for several days and, they replaced the body control module. The truck drove well for several weeks, until 6April, when same problem occurred. The new battery I had purchased was replaced with a new battery by dealership. I got truck back 19 April. The same problem popped up again on 23 May and, the truck is at the dealership at this time.

 

open one batt cable, measure leakage after a minute it should be apx 110 milliamp. 1/10 amp.
read volts after rest, apx 12v. start volts go up to 15 briefly then drop, 14,13 volts depending on speed, loads etc.

 

I am going to advise my service rep re the info all of you have provided. I will ask that the battery terminal connections be replaced. To be sure I get info right, I'm going to print out the info provided. Thanks!!

 

the only way a deale can/will replace the batt connectors is to replace the entire cable with the same factory connectors. i doubt that they would modify the cables with good terminals. beware!!

 

The Dealership would be the absolute last place I would take a vehicle for work.


BTW replacing the battery terminal connectors is a 10 minute super easy job.