I'm looking for a Wiring Schematic for my 1999 GMC Sierra 1500, specifically up and down stream of the IGN0 Fuse.

Trying to hunt down why this fuse keeps blowing now.

Any help or directing to where I could find this would be greatly appreciated.

Thanks

 

Get yourself an AlldataDIY.com account. 5 years is pretty cheap and has EVERYTHING.

 

Ok, so I found 2 wire schematics with fuse IGN0 labeled, can you please help me understand them and hunt down the possible solutions with these?

Also, I removed RTV from MAP and swapped to a different one.

O2 Harness seems fine and if I log I am getting normal reading from them.

Fuel pump primes up fine.

Here are schematics of IGN0:

 

Bump for schematics found

;-)

Any help deciphering?

 

For the schematics found and your problem (I don't know that they're the correct ones but they look right) your transmission harness may be pinched/shorted to ground. The only things on IGN0 are the Transmission, PCM and Cluster. I would definitely focus on the transmission harness though as it runs down the back of the engine and is the subject of pinching on swaps.

You can unplug the cluster to rule a defective cluster out. Unplugging the PCM should rule that out.

Basically I would stick a multimeter (preferably one that has Tone on Short) in the IGN0 fuse downstream pin (easy to find out lol) and test for Short to Ground when you wiggle harnesses, disconnect plugs or perform the triggering actions.

 

Any suggestions on the best way to get at the transmission harness now that the engine is back in and what to look for?

 

Check my post, I edited it some more haha.

You can reach behind the intake manifold to wiggle there and you can go under the truck to access the transmission harness and connector.

 

I REALLY appreciate the help man.

I really hope it isn't the transmission harness line though, gonna be a pain.

But I definitely do remember getting crazy in that general area to remove the bracket it is held on by for the bellhousing bolt. So that would definitely make sense. Just dont wanna have to mess with that...

Blah