Good morning fellas, I lost my constant 12v @ the GPR and I'd like to trace it out. The truck runs when plugged in, wts light works... Can someone post the schematic for the GPR circuits? Thanks guys.
The wrench in the works would be I'm a Cali truck... Another oddity would be that there is no glow plug shunt visible, so this looks like a std federal gpr.. Kinda strange, tho this is the first time I've taken a look at any Cali emissions GPR circuits.. On the attached schematic where is the "B+ starter solenoid (fusible link)" located? Brad, do you have the schematic?

 

Did you lose the big 12+ (line side) or the little 12+ (coil) of the GPR?

The Fusible link is in the line side, and it is nothing more than a couple thinner points in the wire between the GPR and where it attaches to get its power off the constant hot lug of the starter relay.

The 12+ for the coil side comes from the PCM, IIRC.

 

Thanks Nate, I lost the BIG 12v from the starter constant big lug on the GPR..
So your sayin it burns through the thinner points if there is a short? Are those down close to the starter or up top somewhere?

 

Starter relay is on the passenger side fender. There are several big wires that use that as a junction point for power. Yes, the "fusible links" are just thin spots in the wire that are designed to burn through if the power drawn is in excess of the circuit's rating. What often happens is that the connections get loose inside the insulation and the connection heats up then deteriorates. You will probably feel the links if you trace the wire by hand.

 

Alright, understood. Thanks for pointing me in the right direction Nate

 

I think the place to start would be to physically trace that wire back to the starter relay and look for any discoloration in the insulation. If the fusible links are gone, I think you'll see it pretty readily in the form of some discolored and charred places in the insulation.

 

Yeah, for sure... The constant hot @ the gpr is charred currently, it could be if I'm lucky smoked right there but we'll see.. Thanks again.