2003 Hummer H2 Wont start or Crank

No crank at all/nothing/nada:

Could be the starter relay, clutch switch/park and neutral switch and ignition switch assuming the battery and connections are good.

You hear a big CLICK then wire go hot on the battery.

You seem to have a mechanical jam on the engine.
I would suggest you remove the alternator strap and the AC strap.

Now then try to turn the AC compressor pully and the alternator pully.
If it does turn I would suggest you remove all spark plug then try to turn the engine .

You should fin what is stuck in there. I had same problem with a AC stuck.
But engin and alternator could do the same.

hope this help .

Hi,

I attached the wiring schematic below, so you have a reference. (see pics 1 and 2) Note: There are 4 different fuses that will need to be checked and the starter relay. All are located in the under-hood fuse box.

First, check ign fuses A, B, E, and the crank fuse. See pic three below for locations. In addition to checking them, confirm there is power to and from them.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Note: Ign E fuse will only have power when the key is in the start or run positions. The crank fuse will only have power with the key in the start position. So, you will need a helper to test them.

If they all test good, we need to check the relay. If there is a different one in the fuse box having the same part number, switch them to see if it makes a difference. If there isn't one, here is a link that explains how to test the relay and circuit.

Do this and let me know what you find.

Take care,

Joe

See pics below.