2000 SIlverado No Start
 

My truck was running fine, other then an occasional no start to where would have to try 2 > 4 times to start first thing in the AM ( usually when cold outside, 225K miles ). A few months back, while driving on interstate the Security lite came on and truck died a couple times within a couple weeks. Coasted to side of road and restarted to drive home with no other problems. Though this has not happened for a couple months. This Saturday morning, it started right up. Though later in the AM, NO Start, and would not start after many tries.

I thought the fuel pump was bad, and was under warranty so replaced > No start. I checked the fuel pump relay, and come to find out a friend who was helping me installed it Backwards. Won't ask for his help anymore ! Installed correctly and No start. Removed the relay and can jump from 30 > 87 and bingo, Fuel pump comes on. Tried starting and No Spark. No voltage on Pin 85 while turning on Key for fuel pump relay.

I think this is connected to the Security lite, and or the possibility that when the Relay was installed backwards, it zapped the ECM ?

I'm going to OHM out pin 86 ( Relay Ground ) to verify a good ground. If not good, I'll check the grounds on the back of the engine, as according to diagrams is where they go.

Thanks for any advice

Ignition switch? Not the key barrel but the switch on the opposite side of the steering column that relays voltage info throughout the vehicle. I had one go out and it caused the transmission to go nuts...never know.

Running
 

In investigating, found a couple wires under the fuse block under the hood that had rubbed together. Also the main power feed to the fuse block was almost broken in half ? Must a been from vibration.... Also a possible loose / dirty connection on the BCM module. Now it will start and run. Time will tell if it's fixed....

If it do need a BCM, does it have to be flashed to the VIN ??

Yes the bcm will have to be reflashed, broken wires typically dont fry computers though, just cause signals to not be received