This is driving me crazy and is becoming a problem that everyone with a Hummer has. Some times it cranks, some times it cranks fine or sometime u wait ten minutes it will crank but security system will lock. Now 2 days ago I got in it went and got something to eat. I noticed on the way back home my tire pressure light came on , then the traction control light came on and another warning came on and I knew none of these were true because it does this from time to time and when everything is checked there all fine. When that happens I turn it off I know the next time I get in it it is not going to crank let it set for ten minutes it will crank. Two days ago after I cut it off the doors locks wouldn't open and then the headlights wouldn't go off. I have had all of this gone over and nothing is ever wrong. It's to the point where now I have been without a car for two days it won't start. You turn the switch on and the check engine light comes on but won't crank. I feel like this vehicle is driving me insane. Don't know what to do, every time it's checked they say everything is fine. Well it's not. Please I need help I am afraid it is going to do this and I will be stuck alone somewhere. This is a nice vehicle and was not cheap I should not have to worry about if I can leave the house in my car . Anyone with a true answer for what's going on.

 

First of all, EVERYONE with a Hummer does NOT have this problem. What I will tell you is that H3s are extremely sensitive to voltage variations, and one of the main causes of electrical gremlins in them are the stock battery cable terminals. If you still have those, cut them off and install some good ones. Many of your symptoms are classic results of low voltage. Second, the Passlock system is a known problem, causing a crank/no start issue that clears up after sitting for 10 minutes. I have never had the problem, but from what I understand it can be addressed with an ignition replacement. Third, perhaps find a better mechanic.

 

Welcome. Please answer these questions.

Do you have a sunroof? If so, has the passenger side floor ever been wet?

Does the little lock symbol in the dash display light up? If so, search "passlock" on google and here.

Your tire pressure light is a separate issue from the rest. Your truck is 13 years old, the TPMS have a spec life of 10 years. When was the last time you replaced the TPMS in the wheels?
What is the tire pressure in all four tires on the ground? They should all be set to 38PSI ... all exactly the same.

As was mentioned, the first modification that should be made to every H3 is to replace the crappy POS OEM Battery Terminal Connectors, they are garbage.

 

After you replace your stock battery terminals and verify your battery is at the proper voltage, there's one more item I suggest replacing (IF it's really a Passlock security issue).

Replace the Ignition lock housing
ACDELCO D1403G

There is a video on how to do this, he replaces only the black portion and it solved the problem. I followed this instruction and it solved my passlock issue. 0 passlock issues since the repair. I tried a new key because I thought the worn teeth were causing a false trip, but it didn't work.

Video=

 

My 07 H3 had many of the same problems. I bypassed the passlock system completely, replaced the battery terminals, and ran new wiring to power on the body control module. It might have been overkill but so far I have had zero more issues. It has only been a couple of weeks since the latest repairs but so far so good.

I hope you get your issues sorted out.

 

Just be cautious where you park it!

 

No more vulnerable than those 100’s of thousands of cars made without any factory theft deterrent system, and dare I say a lot less desirable to thieves. If I’m stealing a car, I want to blend in. Hummers don’t do that.

 

38PSI?!?! Really, Doc?
Label on door jamb says, 30.

 

With OEM tires.
If you have a sticker on the B pillar that states 265/75R16 - use 34-35psi as a rule of thumb
If you have a sticker on the B pillar that states 285/75R16 - use 37-38psi as a rule of thumb

With aftermarket tires. Due to the possible change in sidewall plys, weight ratings, etc.
Fill to 35psi and chalk test both front and rear. Then either release air or add air for optimal full tread contact all the way across the tire.

 

How much did your insurance rate increase, after you notified them that you no longer have a theft deterrent system?
The real problem is the connector to the switch. Simple fix!
Now that you bypassed the passlock, its just a simple pull and turn on the ignition lock cylinder.
Just don't be bragging about it to those that know where you live.