No Start 6.5 Diesel Hummer H1

[mpwr99]

I have a 2002 hummer h1 with the GM 6.5 deisel engine and yesterday pulling out of the garage the damn thing died. After 5 minutes of looking through fuses i found a fuse in the engine fuse box labeled ALT IGN. I have no idea what this fuse is or does or controls but its a 20 amp fuse and i replaced it 2 times and ones i turn the key the thing blows. Does anyone have any idea what this fuse is for and have had this happed before?? thanks JDMDC@AOL.COM

[ssgharkness020147]

Sounds like you have a short somewhere. You are able to start the truck right? If not then it could be a bad glow plug circut. If you can start the truck and it is then stalling and or blowing the fuse deffiently start hunting for shorts. I have heard (and would start looking here) that the main engine harness located on top of the engine on the drivers side can devolp shorts in it. Try starting there by making sure you have no exposed wires.

[mpwr99]

hello.....no the truck does not start. i mean it will cranck and cranck but no start. Right when i turn the key it pops the fuse.

[Big Z]

Might be a Bad Ignition Switch!

[ssgharkness020147]

Is the fuse in the engine compartment, or under the dash on the pannel. It would help to know the number of the fuse if its under the dash. I think though if you cannot start the truck, and its popping right when you turn the key its the glow plugs. After the fuse blows the the wait light go out or does it continue to cycle?

[NoMoGMPG]

Glow plug controller (passenger side rear of the valve cover) is probably shorting to the body. Happens when the body mounts start to sag/compress or the engine mounts get mushy. Look for black burn marks above the large red wires connected to the studs of the controller.

[mpwr99]

hello the fuse is in the engine compartment and the description of the fuse is ALT IGN. yes the wait light stops cycling.

[Carbine]

Verify power at the fuel shutoff solenoid on top of the fuel injector pump.
If you have power then connect and disconnect that live circuit and see if you hear a click at the solenoid. That should tell you that you have a good solenoid. Not always but a 90%ter.
Don't be too quick to blame the glowplug controller, some of those can be bypassed. If you want to be sure if your glowplugs are cycling just watch the volt gauge and look for the drop and if it does you are cycling.

Chances are if the truck was running you lost power to the shut off solenoid somehow.