00 ZR2 blazer. It won't crank or stay running without a jumper wire in place from pin 85 of the starter relay (coil ground) to battery negative.

I can get the truck started by jumping the relay to ground and then having my helper turn the key to "start"...it will start....run....and then die as soon as i remove the jumper ground wire.

I am confused pin 85 gets good continuity to ground with the key "off" but i lose the ground as soon as the key switches on.

One question of mine....is pin 85 supposed to be a switched ground? If so what switches it...the bcm? pcm?

Also why did the truck shut off when my jumper wire was removed?

 

Ok was just thinking some more. The fuel pump is also not running for 2-3 seconds after turning the key to "on" position. From the few wiring diagrams I have it seems "G102" may be my culprit. It seems to ground a few items including the fuel pump relay and starter relay.....my question is where is g102? lol

 

By pin 85 I meant pin 86