91 APV blowing fuses

[pinkster]

I wrote last week about a dash short. After a little research the circuit that is giving problems is the Ign circuit. It carries the A/C compressor relay, audio alarm module (i took this out already) Cooling fan relay, cruise control, daytime running lights,(don't have), generator, heater and A/c control assemb., solenoid box, vehicle speed sensor buffer, pusher fan relay coil, rear window defogger relay, instrument cluster, temperature door actuator. I disconnected the speedo because it always acts up, and thought i had it curred, but the next time I drove it,I blew a fuse again. I am thinking that I have a bad relay somewhere, but where are they if they are not located under the dash below the fuse block. I also had a breaker in place of the ign. circuit fuse and was test driving and it started acting up and the speedo jumped up and i had the speedo disconnected. Something is not right. I am mechanical, but electrical problems are not my strong point. any ideas? Terry

[jeffcoslacker]

I'd put everything back together the way it goes, with a new fuse, and start moving wiring around under the dash and in the column while someone watches the speedo.

Do thins with the ignition on, motor off, and see if you can get a reaction from the speedo while doing this. If so, you may be able to narrow it down and find an unwanted path to ground or a wire pair that are crossed up.

If that didn't show me anything, I'd pull all the relays other than what is needed for basic operation, and drive it. I'd put them back in one at a time until the problem returned, then start looking real hard at that circuit.

[jeffcoslacker]

Also, just for kicks, try pulling the FUSE for the rear defroster. I've found them to be a common cause of overloads. Since the relay is powered through the side that's giving you trouble, it's possible the power feed for the defroster itself is crossing up with the relay contacts inside the relay, sending a high-amp feedback through the ign power feed. That'd do it, and probably without popping the defroster fuse.

A spike like that in power feed could explain the speedo twitches, too.