M923A2 electrical issues.

[CAPSARME]

Recently my 1991 M923A2 has started acting up. I first noticed the ABS light coming on randomly. A few drives later and I noticed the volt meter pegged at random times. Lastly, the horn decided it was going to come on and not turn off.

I unplugged the steering column and the horn is still on. Had to unplug the solenoid at the horns.
I looked for chafed wires in the cab and any rodent nests, but everything up under the dash and under the hood looks to be in great condition.

Truck wiring is 100% original and in molested. Batteries are a year old and test good.

any help

 

[CAPSARME]

Also, I can not hear the typical clicking of the abs unit when it does its self test.

 

[CAPSARME]

Another update on the horn side anyway.

tested the horn switch. Connected one lead of my multi meter to ground, and the other to the horn switch terminal at the base of the steering column. No connection unless I pressed the horn button. Then I had connection. Checked the wire #25 that plugs into the horn switch terminal. That wire has ground all the time.

went up to the horn solenoid. Wire 26 has power all the time. Wire 25 has ground all the time.

I assume that wire 25 is shorted to ground at some point in the harness. Once it stops raining, I will climb up and see if I can find out where that is taking place.

 

[G744]

May you not get stuck behind a group of Hells Angels with that...