GMC Van electrical problem

[jdubreck]

I have no power at the Aux Power lead when the key is on. This lead feeds switched power going to an aux. fuse box on this GMC Conversion van.
I just added a set of high powered lights, connected them to the aux fuse box - and now everything connected to that (top half) of the box is dead.

I traced the main power lead to the Van's fuse panel - and it is a dead lead - but I cannot find a fuse that powers that large wire. So, 1st question, what feeds the AUX connector on the fust panel. I know that the lead is normally "off" when the key is off. But now, even with the key on, it is a dead wire.

[maxwedge]

Welcome to AF, please post the year.

[jdubreck]

it is a 1990 GMC Vandora 2500 with the Explorer Van Company conversion package.

and I just noticed that I misspelled "fuse panel" as "fust panel" - oops.

I am thinking that a relay is normally pulled up by placing the ignition key in the "on" or "aux" position... that clicking is not happening.

I cannot find that relay to see if 12 VDC power exists at either the coil of the relay (with the key on) or if power exists at the input to the contacts of that relay.


Thanks a bunch for your attention to this!!
-Jim

[maxwedge]

This sounds like an aftermarket modification. you will need to back trace that circuit.

[jdubreck]

I have back traced the circuit to the stock fuse box.
The 'ACC' terminal at the top of the stock fuse box is dead. What powers it?
I cannot get to the factory wiring to see which leads run to the relay that GM put in place to allow the ignition key to enable power to the Radio and other items that are powered ONLY when the key is on.

Obviously the headlights are powered at the fuse box all of the time - but other items come on ONLY when the key is on. What powers those items and where is that power source thingy located - in the steering column or under the dash - and if there, where under the dash - it is a mess of wires and boxes, etc.

Thanks,
Jim

PS, All of the after market additions are ok - when I pull the lead that is connected to the front of the fuse box (to the ACC terminal) and put power directly on it, all the stuff connected to it works - so it is the factory-wired power going to the rear of the fuse box that I cannot trace to its (key enabled) source.

[maxwedge]

Check the " fusible links at the starter harness off the main bat terminal at the solenoid.