The Stovebolt Site Forums The Shop Area The Electrical Bay New Wiring Harness, 2 issues (1951 1/2 ton)

Me and a bud got the new harness in yesterday after several hours, several beers, and the associated busted knuckles and cramped necks... was a fun day, but not one I'd like to repeat any time soon.

All is working as designed minus two things.

1. Ammeter shows discharge when revving the engine right after starting. I think this is as simple as reversing the wires on the meter?


2. I added an original style trumpet horn with the two leads, one to the button, one to the ammeter.

When we first attempted to hook up the battery, there was obviously a problem. Big spark when touching the bat leads on the terminals... We isolated this to the horn hot wire. If we disconnected the horn button from the harness, via the mast bearing, we still got a short.

If we left the hot wire to the horn in place and connected the battery the horn would sound as soon as the battery was connected.


I could probably fix this with adding a horn relay, but I'd like to keep it as original if for no other reason than just hardheadedness.

The mast bearing is original, but I soldered on a new wire before we proceeded with the harness install. The contact spring bushing and contact plate are new.

Been reading a lot of old posts, but haven't gotten anywhere yet.

Any ideas, or should I just add the relay?

Thanks in advance!

Lee

I would definatly add a relay but there must be a short in the horn. Have you tried reversing the wires going to it. It needs to be corrected or you will burn up the relay. If the amp. gauge goes to charge side when you turn on the lights or something, yes reversing the wires will correct it. Sounds like you did a good job if thats the only problems you have.

Thanks a lot! I spent many hours labeling and relabeling the harness to minimize errors during the install.

The ammeter had stopped working on the old harness, so I didn't really know which direction the needle would move.


I think I found the solution...

Correct Brush

http://secure.oldchevytrucks.com/HO...ITS-IN-STEERING-WHEEL/productinfo/EL520/

Brush I Put In...

http://secure.oldchevytrucks.com/ST...TACT-53-72-WITH-RELAY/productinfo/EL525/

I bought the wrong part apparently, I didn't realize it until I looked on Jim's site to see the difference in the two units. The right one above is just like the original one I removed when I pulled off the steering wheel.

Live and learn!

I still think you have a problem in the horn. If that brush was shorted the horn would blow all the time. If it was open the horn would not work.

Right, that makes sense. I'll play around with the orientation of the wires on the horn. Is there a ground and a hot side for the 2 terminals? When I tested it when I got it, I just simply attached two leads to it and a battery, worked ok then. Sorry for my ignorance lol.

Jeeze, when I started this rewire I figured the horn would be the easy part.

Just took the horn out, wired it directly to the battery, BEEP!

Before I took it out I unmounted it and connected the two wires in different combinations nothing.

Yesterday we were able to get the horn to blow continuously when the button wire was removed, that made sense. Now I have no idea. Got to be a ground issue I haven't addressed because it sparks a bit when both wires are connected to the horn and the button.

Should I run a ground from the horn somewhere?

The previously mentioned reversed wires on the ammeter shouldn't affect the horn should they?

Thanks.

Lee

Do you have the correct horn switch in the steering wheel?

I don't. The one I have is for relay equipped trucks. I figured that out after the fact. I have the correct one on order. I'll be adding the relay back eventually, I'm just satisfying my curiosity on the original setup first. The old sparton horn worked off a relay with the original (non-relay) horn switch in the wheel.

Seems I did read somewhere that the relay type switch can burn up when connected without a relay? Dunno.

Checked voltage today on horn feed, 6.4 volts, same as battery. Horn works when hooked direct to battery so I've kinda isolated it to my button setup and or a ground.

Pulled the horn switch in the wheel just now... I know why this switch is designed for a relay setup. The thin spring inside had compressed itself, I assume from the high current/heat, and made the switch inoperable. One more piece of the puzzle in place...

Update....Success!

Horn works great now, added a horn relay and a ground.

Many thanks to all who have posted with ideas!