70 Roadrunner horn trouble

[clazar]

I went to "beep" "beep" someone today & the horn stayed on. I pulled over & pulled the wire connector at the horn. What's the diagnosis procedure for fixing this problem?? I also checked the relay after I got home & it was very hot.

Chuck

 

[moparedtn]

Well, I just got my horns all wired up (reproduction wiring harness, relay, etc.) and the first time I went to hit it, the same thing happened - they stayed on!

At least in my case, it wound up being the wire in the steering wheel being shorted under the horn ring (previous owners' sloppy work). On these horns, when you depress the horn ring on the wheel, you're actually completing the GROUND side of the loop, not the power - there's 12VDC at the horn relay at all times.

The horn relay can also stick, so if you can't find a short/ground in the steering wheel or elsewhere (real simple wiring to trace), a new relay is still available at the local auto parts for about $11.
Good luck!

 

[Archie340]

Great advice, shouldn't be to hard to track down. Mine was more severe, the primary wire from the battery overheated and melted several wires including the the horn and ignition wires into one causing the horns to receive constant power. Lots of melted spagetti, but thats more of a worse case scenario.

 

[clazar]

The relay is 3 yrs old & all new dash wiring. If I have to take the column apart, what should I look for ??

Chuck

 

[clazar]

Bump

 

[bigmanjbmopar]

Button on steering wheel pushed in and stuck, pull the wheel off and repair the button.

 

[moparedtn]

The relay is 3 yrs old & all new dash wiring. If I have to take the column apart, what should I look for ??

Chuck

The wire that plugs onto the horn ring inside the wheel passes under the ring and down the column tube.
Mine was pinched under the chrome horn ring. Three screws and that comes off. You'll see right away if
the wire is pinched once you take that off.

 

[clazar]

Pulled the strg whl off & can't find any problem. I put on a new relay. I disconnected the black wire at the wheel & had the steering wheel off. I connected the battery & the horn still blows. There is all new wiring on the car & no visible problem. What should I check now ???


Chuck

 

[clazar]

I now also lowered the steering column & disconnected the turn signal wiring harness from under the dash. Connected the battery & no horn blowing. Do I need to replace the wiring harness or dig deeper into the column ???


Chuck

 

[moparedtn]

Well, sounds like you now know the problem lies between the column harness plug and the horn ring, eh?
You could just run a new ground wire up inside the column and tie it into the plug and the horn ring.
Don't even have to put the column back up in the mounts to try this and you'll once and for all know, since
you've eliminated other possibilities pretty much.

By the way, do the turn signals function ok?

 

[clazar]

Well, sounds like you now know the problem lies between the column harness plug and the horn ring, eh?
You could just run a new ground wire up inside the column and tie it into the plug and the horn ring.
Don't even have to put the column back up in the mounts to try this and you'll once and for all know, since
you've eliminated other possibilities pretty much.

By the way, do the turn signals function ok?

good question about the turn signals. i'll check those after dinner.

do you know which wire is the ground wire in the plug for the horn??

Chuck

- - - Updated - - -

I checked. The turn signals & hazard lights do work properly.

Chuck

 

[bigmanjbmopar]

Did you find the switch at the steering wheel? is it working? you might have to check it with a meter.

 

[clazar]

bump

 

[clazar]

Bump

 

[5.7 hemi]

The contact plates are stuck together. Use a small flat head screw driver and open them up. Also while your there, take some sand paper and clean in between the 2 plates then use some die electric grease between those plates.

 

[clazar]

The contact plates are stuck together. Use a small flat head screw driver and open them up. Also while your there, take some sand paper and clean in between the 2 plates then use some die electric grease between those plates.

I not sure what contact plates you're talking about. I took the horn ring assembly off the steering wheel & the horn still blows. I'm getting ready to get into the column & check the wiring harness . I also disconnected the turn signal wiring harness & that stopped the horn. Any suggestions are surely needed.

Chuck

 

[440+6]

This is what the switch looks like, there are two contact plates held apart by springs, when the plates touch it completes the circuit and the horn blows.
Make sure that's not the problem first.

 

[moparedtn]

Here's your wiring diagram:
http://www.mymopar.com/downloads/1970/70BelvedereGTXSatelliteRoad RunnerB.JPG

 

[5.7 hemi]

440+6 said it right!

 

[clazar]

I do have that off the steering assembly already. It isn't stuck. I believe it is working properly. I have a new relay hooked up, the switch is off the car & when I connect the battery, the horn beeps. When I disconnect the turn signal wiring connector under the column, it stops beeping. Can I assume something in the wiring harness is bad ???

Chuck