2004 gmc sierra starts with remote only

Hi all, this recently purchased truck is not starting anymore. It started fine (with the key) at the dealer when taking it home. At home when turning the key DRIVER 1 is displayed but doesn't even attempt to crank. Using the remote it starts every time. I think the remote is aftermarket (Autostart). Does anybody have an idea where to start looking? Thanks"Good judgment comes from experience. Experience comes from poor judgment."

-unknown

I'm pretty sure this truck is equipped with a passlock 2 system. In that case I would say it's the ignition switch. The passlock ignition switces supply a resistance to the computer in order to start. Sometimes the switch goes bad (ie wear) and it no longer supplies the proper resistance. Since the remote starter has a bypass module in which the resistance has been learned, it still starts the truck as it's putting out the proper resistance. Thats my guess only, you'll have to further diagnose to make sure.

Along with yellow_cake, there are other possibilities too. So here are the three possibilities: 1: The Autostart unit has a starter-kill or anti-grind relay installed. (Or, it may even be a full alarm/starter combination system.) In this case, if the starter kill is engaged, the engine cannot be started by turning the key, in order to make the car more difficult to steal. How are you unlocking the doors---are you turning the key in the door, or using the OEM GMC remote maybe? Try pressing Unlock on the Autostart remote and see if you can start the car. 2: Vehicle's ignition switch is bad, or the Passlock part of the ignition switch is bad. If it's a Passlock problem, you'll often (though not always) see the yellow "padlock" symbol flashing in the instrument cluster when you try to start the engine. Also, the portion of the ignition switch that powers up the starter wire could have simply failed. 3: It's possible that somehow during the installation, depending on the way the connections were made, that the truck's starter wire under the dash has broken in half, and now the "key side" of the wire is going nowhere. My opinion is to try #1 first, because that requires no tools or vehicle disassembly. If you do find out that the Autostart unit has a starter kill connected, be sure to find out where the valet/override switch is installed, and look for an owner's manual online.......you'll need to have this information in case the battery in the remote control fails, or you'll be stranded.

It's not my truck, but I will pass the info along. Thank you very much guys. I will post any updates/results & solutions for future reference in case other people encounter the same problem."Good judgment comes from experience. Experience comes from poor judgment."

-unknown

Does it have a Past Time or some other device that a finance company installed on it that may be preventing it from starting?

I don't think so, but will check. Adding to the problem is the fact the truck comes from an auction. You never know what you get."Good judgment comes from experience. Experience comes from poor judgment."

-unknown