2008 Hummer occasionally will not start. Completely randon when this occurs. Can sometimes wait a few minutes and it starts and sometimes much longer. This has basically been happenning since new. Dealer replaced fuse box and still no fix. Thank you for your time. Gary

It's unlikely that such a new vehicle would have a starter or solenoid problem. If it cranks over but won't start, try jiggling the shifter while in Park, or put it in Neutral. It could be a defective Starter Safety Switch which prevents the car from being started while in gear. Good luck.

Do you hear a clicking sound around the engine when it doesn't start? Have someone try the starter while you listen carefully under the hood for the source of the clicking. If it comes from the starter/solenoid area, you will need a voltmeter or test light to test for 12 volts at the battery side of the solenoid (light on or 12 volts always while attempting to start). If light goes out (12 volts goes to zero), then replace the positive battery cable that connects at the solenoid. Next test is at the solenoid other heavy terminal that connects directly to the starter motor. If the light never goes on (12 volts never appear) during start, the solenoid is bad and should be replaced. If light comes on (12 volts appears), then the starter motor is bad and should be replaced. (It likely has a dead spot in the commutator.)