Why Doesn't My M35A2 Horn Work ?

[RollingThunder19]

Any specific inline fuse amp rating?

 

[pjwest03]

That looks like the outline of what used to be on my firewall. Where can you get one? I've looked around but found little

The part number is M13512/1-1. I usually order electrical parts from Saturn Surplus or Erik's.

 

[pjwest03]

Any specific inline fuse amp rating?

The breakers are 15amp. A 10 or 15 amp fuse should be fine.

 

[RollingThunder19]

Okay thanks for all the help and info. I'll order a new breaker and see how things go

 

[RollingThunder19]

Okay so update on horn. I got a 30amp inline fuse and ran a wire from positive on battery up column and soldered it into original wire to make it a constant hot. Once pressing the button fuse blew and smoke came from button assembly. Did I do something wrong? Any ideas?

 

[pjwest03]

The steering column and the horn button are used to provide a path to ground. The 24V feed should go to one side of the horn. The line from the column and button goes to the other terminal on the horn. Sounds like you connected the column to 24v. That would be just a dead short when you push the button.

 

[RollingThunder19]

So just run the line from the battery to one horn terminal?

 

[pjwest03]

Yes. 24v to one terminal of the horn. The horn button/steering column connects to the other horn terminal.

 

[mil]

I wonder if 10-13 years later all the horn's (and other problems-except plan-demic) were resolved?
Or nobody writes any more. I had acquired, fraudulently, oh, criminally described bobbed M35A2.
Crawling through 1000s problems, I've finally managed to get pressurized air system working to
120psi, and heureka - still not done - registered opposite problem - the horn started (unpleasantly)
bleat, once the pressure built over 60psi - no didn't touch the horn switch, so switched engine off
and dashed to release air from the tanks, for bleating continued until no air. Removed horn switch
and for sure both el. connectors from horn solenoid. Started engine, build up air pressure and....
horn started to blast again anyway. Engine off, quick release air tanks to stop ever working horns.
(Also found major air leak from solenoid feeding elbow). Assumed "stuck" solenoid, removed and
re-tested on regular air compressor, yes. Hence, ordered a new solenoid and hoping for resolution-
maybe then will experience horn's total mis-function as previous entrants into this thread?

 

[mil]

I did though it vanished ?

 

[pjwest03]

I haven't experienced a stuck open with the deuce horn solenoid. I had one that stuck closed. Tends to be a buildup of dirt or corrosion over the decades. I have seen solenoid valves in industrial machines with the problem you seem to have.


The main thing I've experienced in all old trucks is the wiring being corroded internally where you can't see it. The circuit will pass a continuity checks but can't carry enough current to operate.

 

[frank8003]

It is a wonder to me thes guys don't burn down the truck
All Your answers are in the TM's