82 HJ47 can only blow one horn. connect the second, nothing?

[calen]

Hi all,

I did a bunch of searching and couldnt find anything that helped solve this problem. I have two Fiamm snail horns that work, tested them. they've been installed for several years now. when driving, they only blow when my in cab batt meter says 14+volts. lower then that and they dont really go. so tried to fix this finally today and left the day with a working single horn. if I have two connected they dont work. just one blows fine. swapped horns same deal. swapped single horns from side to side, same thing. with a meter on one side at a time, pushing the horn button, the meter reads 12+v. If i connect both horns to one horn wire set they dont go. both sides. but one horn at a time works fine. Fuze is fine, and these cars dont have a relay according to the schematic. what could cause this?

 

[charliemeyer007]

Is your system 12 or 24 V. Corrosion is resistance - current can't flow - clean all your contacts hot and grounds - look at your horn button. Voltage is "water pressure" when you need 14 V in a 12 volt system to make something happen that's telling there is too much resistance for the current to flow and do work.

 

[sadovnik]

Horn relay tested out OK? Or do the 82s don’t have one?

 

[calen]

Horn button is good. played with all the connections today so they are clean. and there is no relay, so im at a loss as to where the resistance is coming from. its pretty simple system no? wires from horn button to fuse box, wires to horns right? gonna try pulling the little contact pads up so they contact the button contacts harder, see if that's the problem? Can the wires themselves fail in some way that they can still work but not completely?

 

[charliemeyer007]

So look carefully at each of the crimped on connectors - corrosion can crawl under the insulation and ruin the wire/connection

 

[wimberosa]

I've had weird similar issues and I'm starting to believe its "insufficient / corroded" ground somewhere
in the steering column. Look there and start touching in a solidly good ground wire into connection
points (e.g. check the steering rod itself to see if the bad connection is at the rag joint...etc).

I'm fairly certain its my problem but it gets even weirder for me. When I get the key turned on...i can
use any of my 3 horn buttons on the steering wheel. If the key is off...only one button works!

 

[calen]

Will do a second deeper dive and do this this week. thanks for the suggestion.

 

[sadovnik]

I would be looking for that horn relay. I can't see the two horns being directly connected to the horn buttons on your steering wheel. There must be a relay somewhere in the circuit. Here's a picture of what my horn relay looks like. It's a tiny little box that sits on the fender.

 

[calen]

I would be looking for that horn relay. I can't see the two horns being directly connected to the horn buttons on your steering wheel. There must be a relay somewhere in the circuit. Here's a picture of what my horn relay looks like. It's a tiny little box that sits on the fender. View attachment 4044564

as far as Ive read, and seen in the schematic, there appears to be no relay.

 

[peesalot]

The horn button switches ground, try providing a direct ground instead of relying on whatever it uses in the wheel as said above, next I would look at the fuse terminals at power supply, I have wierd issues like this with blinkers & fuel switch valve, a cleaning/check of the fuse / terminals at fuse has been the point of voltage loss.

 

[charliemeyer007]

So your horn button goes to chassis ground. On my 72 I installed a # 2/0 red wire to the starter and connected the loom + to the + battery terminal. I ran a black # 2/0 wire to the block from the - neg battery terminal. I used the old #2 black wire to go from that block ground to the frame ground under the brake line T. I ran a #10 wire to the cab from the frame ground.