Strange Starting Problem

[Sundown94]

Back in May, I had a problem where I would turn the key but the truck would not start. The battery was fine, the lights all worked, the dash lit up, etc. It just wouldn't start. Had it towed to the shop and when we got there, it magically started up as soon as we turned the key. The mechanic said he scanned for codes anyway and that everything seemed to indicate that I needed a new ignition switch, so we put one in.

Last night (about six months later now), I had a similar situation where the the truck would not start. So my wife picked me up (I just locked the doors and left the truck there) and this morning I drove back to the truck with plans to call AAA so that it could be towed to the shop. BUT, I put the key in and it started right up. So I drove it to the shop and the mechanic is going to try reading codes again.

Here is what is similar (IMO) to both cases: 1) the truck decides to start after I leave it alone for some period of time...so in the first case, it started after it was towed to the shop, while in the second case it started after I left it in the parking lot over night. 2) in both cases, I had only started the truck and drove it a short distance (about 1 mile/5 minutes) and then I had the problem starting it afterwards.

Is this really a problem with the ignition switch, or is it related to something else such as the security system? I mean, if it was the ignition switch, why would it magically start after just sitting there untouched over night? Instead, I am wondering if the security system encountered a problem and has some kind of reset period (like maybe an hour needs to go by and then it resets itself or something). The battery was definitely not dead (and just to be sure, I did try jump starting the truck before I gave up last night). Any ideas???

Thanks!
Steve-

[twr]

hi check the voltage down at the starter when it happens, have someone turn the key over and check the starter with a voltmeter or a test light. I know alot of hummers had problems with the ingition switch. Maybe the neutral switch or the starter itself. Hope this helps.

[Hellz]

shifter might not have been fully in the park slot. i had this happen to me before. i turned the key to release the shifter and moved it out and back into park. started right up after that.

[HUMTECH]

My guess is the starter. you can check for voltage at the starter or next time it wont start, hit the starter with a hammer, if it starts you need to swap it out

[Sundown94]

Thanks for the suggestions so far. As an update, the truck is now sitting at the shop and no longer starts, no matter how long we wait (eliminating my thought that waiting might be correcting the problem). Apparently I got lucky when it started one more time which allowed me to drive it over to the mechanic. He has not been able to start it since then. But he attached his scanner and said that it is coming up with some kind of communications errors (can't remember what they are) and other codes that make him think there is something wrong with its ability to read my keys. They are not the codes that are related to ignition switch problems. Whatever they are, he said the problem is computer related and needs to be towed over to the dealer for further testing because he does not have the appropriate equipment.

If there was a problem with the starter (which was just replaced last year due to a problem with the gear staying engaged for a split second too long and making a horrible sound), would the computer produce "communication error" codes? Or do you think he is right that there is something wrong with my keys/security system?
Thanks!
Steve-

[HUMTECH]

Sounds like something is bringing the class 2 line down. Do you have an aftermarket remote starter installed? If ya do check for a wiire splice behind the data link connector(where the scan tool plugs in) if there is a splice there disconnect it and see what happens