My 2004 H2 Hummer has lost power while driving then suddenly regains power while coasting remaining in Drive gear. The Passlock symbol light flickers intermittently while driving but usually causes no issues. Except for two times when the Passlock light came on: then all the dash lights came on, bells went off and all the gages went to zero. As the Hummer was coasting with only manual steering and brakes it suddenly regained power and the gages all went back to normal. This loss of power then regain of power all happened in Drive gear and with no time to pull over. Does anyone have any idea what is causing my Hummer to do this?

 

I would replace the electrical portion of your ignition switch after confirming that your battery cables are clean and tight.

 

Thank you calif phil for your help!
The Ignition lock cylinder was replaced last year. Not being a mechanic i don't know know or understand if the electrical portion of the ignition switch was replaced?
Here are the service/mechanics notes as was written on my invoice:
Replace the IGN Lock CYL. It was binding most of the time. Worn Tumblers and key causing IGN to intermittently bind in the Locking Housing. Removed the ols IGN Lock CYL and disassemble as needed to obtain the code from the original tumblers, Re-keyed new IGN Lock CYL. Greased aas needed, re- assembled all, clear all DTC's, recheck ok.
Did the mechanics notes say anything about replacing the electrical portion of the ignition switch as you recommended? My H2 Hummer died while driving once before the mechanic replaced Ignition lock Cylinder and one time after the replacement. I will have someone confirm that the battery cables are clean and tight as you recommend.

 

There are two parts of the ignition switch and it's easy to get confused as many people do. The ign lock cylinder where you insert the key is what it sounds like your dealer replaced. The ignition switch is what is on the end of the lock cylinder and that is the electrical portion of the ignition switch. You could also have other problems such as a bad crank sensor or a fuel pump going bad. Please keep us updated.

 

I will update. Thanks again calif phil for your help!