H3 Weird electrical issues again

[amrg]

My truck is having the following recurring issue. As I would be cruising, when I step on the brakes moderatly, my headunit would go off for a slight instant and my lights flicker once. I could repeat this sometimes. I also notice that on idle, my headunit would stop making any sounds for instants.
I recently had my car fixed for an issue were as I am cruising my doors wld suddenly lock/unlock, sometimes several times. Dealer claims to have changed the battery terminals and the battery then and that solved the issue.
I now also have had two instances where when I try to switch on the ignition, nothing. No noise, no dim lights, no starter noise nothing as if battery doesnt exist (dealer claimed that they changed the battery several months back on warranty). Anyway, I wld pop up the hood, get jumper cables, by the time I would have the cables attached to my battery (not even connected to the others trucks battery yet), the truck goes back to life and starts normally.
Wtf is going on?

 

[06 H3]

Bad battery terminals...

Before I swapped mine out the same thing would happen. Pop the hood to jump it and it goes to life before I even get the jumper cables hooked up.

To test this, next time it happens pop the good and wiggle the battery terminal, if it goes to life that's the problem. Even if the dealer fixed it they are still using piece of crap oem terminals

 

[Mr_Rich]

The battery cable terminals aren't a "Hummer H3 problem", they are a GM problem. The same discussion has taken place on the Corvette forums. At minimum, take an abrasive pad to the terminal of the battery and inside of the battery cable connector and re-install. It should be okay for a while...

 

[amrg]

I went to the terminals today, theyre pretty tight and zero corrosion on them. Checked the battery and still perfect. I now seem able to repeat the symptoms while the truck is coasting by simply holding the window buttons up to close the windows when theyre fully closed (usually the cabin lights would dim abit when i do that) In those instances the dials also die, In addition to the radio and head lights.
Any suggestions?

 

[bebe]

Not sure specifically what you mean by the Battery is perfect (The charge, amp levels, no corrosion?) Anyway, the problem is in the battery itself, where the terminal or "post" connects underneath the top.

Mine started doing this as it went bad all together, I replaced it with a blue top and I've never had the problem since.

 

[Happy Hummer]

I'm going to also offer an opinion from practical experience. Both my GF's & My H3 have exhibited unusual behavior at times over the years and to minimize the weirdness factor we did the following;* Replaced her battery and terminals* Checked ground connections at frame* Pulled connectors and sprayed cleaner in computer on firewall* Replaced Neg. terminal on mineChris

 

[Mr_Rich]

Having worked in electronics for thirty years there are times when a visual inspection in NOT enough. I have been bit by "visually" inspecting electrical connections more than once. Sometimes you have to break the connection, buff the surfaces, and re-connect. A battery connection is tricky since the voltage will stay the same when it is checked at different points of the circuit. However, the amperage the circuit will carry will make a difference with a dirty connection and not carry the full amp load that is needed.