[Scout]

Need help with my horn relay switch. When hooking up power at the battery the relay closes, contacts click closed. I can measure voltage at both wires (black & green).It measures 9.4v at the black wire in plug and 12.5v at the green. With the steering wheel off I am also measuring 9.4v running right to the horn button ring. With the plug disconnected from the relay and contacts open, the black wire spade measures 12.5v and the green measures 0.0v. Any ideas?

["QUICK-SILVER"]

Is this car orginally a L6 or V8 car?

L6 cars had three wires on the horn relay:
1. Red or Black from battery (+)
2. Dk Green out to horn/s
3. Black to Firewall Junction Block and then Black up steering column to horn button.

V8 cars the horn relay was also used as a junction block to supply power all over the car. To battery (+), alt or gen, into ignition switch, fuse box, etc.....
It had two wires plugged in.
1. Dk Green or Black to horn/s
2. Black to Firewall Junction Block and then Black up steering column to horn button.

So on your car info that's posted, you are leaving out a wire.
you said
"With the plug disconnected from the relay and contacts open, the black wire spade measures 12.5v and the green measures 0.0v."

That would make Black the battery (+) wire and Green the horn/s wire.

If it's a L6 relay some wires may be crossed up.

You didn't say if the horn/s blow or not. The voltage drop you found in your first test sounds normal if the horn/s are blowing or stuck and quiet.

So let us hear more about other wires, relay terminals, and such.

Clay

[Scout]

Clay i checked the horn itself today and found it to b faulty (no blow). So I changed it out with a good one. Now when applying power to the relay the horn blows constantly (contacts closed). At the junction block on the relay is the starter power wire, a red wire to alt. or regulator and the power cable from battery. Even with the two wires disconected from the relay junction block (just pos lead hooked up) i get the same relay problem. The contacts close and horn blows). Its the black wire spade that is hot (12v) with power cable hooked up,contacts open and black/green wire plug disconnected.With power hooked up at the relay, every time I hook up the green & black wire plug to the relay the horn blows (contacts close) As if the horn button is always depressed. I have the steering wheel and horn components off the column except the brass ring. I have checked continuity though the entire circut and its good. Whats next?

[Scout]

This is a 389ci and a factory Delco relay. I have a brand new relay that does the same thing

["QUICK-SILVER"]

I gotcha
Sounds like the black wire to horn button is grounded out somewhere. Just about has to be. Everything you posted is as it should be except for that. Resistance through the windings in the relay cuts the volts/amps drastically. That's why nothing burns up when you ground that terminal out to trip the relay.
Having continuity tells you the wire isn't broken. Need to unplug it from the relay and check for short to ground. With it unplugged you can use a test light hooked to B+ instead of ground to check for a short. Continuity to ground or Ohms resistance will show the same as the test-light test.
If it is shorted, start unpluging to rule sections out.
Good Luck Hunting
Clay

[Scout]

Clay, thanks. Hey i've gone through all the in line connectors/ plugs in the black wire circut one section (unpluged at relay to end of wire at unplugged bulk head connector on firewall ect) at a time for continuity from relay to horn button ring. Not sure what to do by your suggestion, not to good with electrical stuff! U say I should check each section for short with the test light off the positive side of the batt? Could u elaborate, not so sure how (dont have alot of experiance here). thanks for your time, gotta b shortin out somewhere

[Scout]

Clay think I know what you're sayin now. Hook test light lead to + and probe wire end at each unplugged connection. If test light lights up theres a short as the break would make a ground. Is that right?

[Pepi]

Originally Posted by Scout

Clay think I know what you're sayin now. Hook test light lead to + and probe wire end at each unplugged connection. If test light lights up theres a short as the break would make a ground. Is that right?

Yes, that is what he is saying, one end to battery + and with other end probe unplugged connection. If lights you will find the short not a break. Break will not cause issue you are having.

[Scout]

OMFG, well started testing for shorts in the horn circuit with test light hooked up to + positive. disconnected relay and bulkhead(at firewall) plugs. tested black wire and sure enough the light lit. So off came the harness wrap and nothing was obvious. Hooked up test light again and while wiggling the black wire and light would go on and off. pulled the wire from both plugs and installed a new black wire. Retested good (no light up). Hooked both plugs back up, Hooked up power and relay closes, horn sounds! Disconnected bulkhead plug and light tested black wire pin in in firewall bulkhead...lights up. Next I disconnected the turn signal switch plug, the half round plug that sits above steering column and tested the black wire from there to horn button ring. Test light did not light, so that section should b good. Still need to find what is causing the bad test at firewall bulkhead to inside car, haven't pulled the fuse box yet. Anybody know where the black wire goes from the fire wall connection, (next junction to light test)? While looking around under dash I notice yet another burnt and broke black wire coming out of the main harness behind the fuel gauge/temp gauge instrument! Looks like a looped (in & out of) harness wire. I am strung out with this mess!

["QUICK-SILVER"]

"I am strung out with this mess! "
Sounds like an electrician talking or you're trying to put lights on a Christmas Tree.

There shouldn't be any more connectors to take apart.
Horn wire should be one piece from the turn signal connector to the bulkhead connector.
After reading through your posts, "I" feel like you should just replace that section of wire.
The harness really needs to be out of the car to repair it correctly. Not saying it can't be done, but???... And Not saying it doesn't need repaired either. It would just be a whole lot easier "for now". That's also if (BIG IF) you're not having any other electrical issues related to the dash harness. No doubt that somewhere something is burned and melted together causing the short.

Earlier you posted that wiggling the wires, under the hood, made the test-light blink. If that's true and not a faulty test-light connection, it's very possible that the short is right near the inner bulkhead connector if not in the connector itself.

I'm going to call this "one of them up to ya's". Only you can see what is there and what you're up against.

Good Luck
Clay

ps, take a chill pill if you have to

[Scout]

Lol! Thanks clay for all the help and I hear ya! Sometime u gotta walk away and well take some kinda pill.....tryin to avoid the whole harness replacement but it may b inevitable. At this rate its gonna take a while but will post results...Scott

[Scout]

Clay, found the problem! Pulled the fuse box and found several melted wires!! Looks like a $450 dash harness is in order! Cant believe it. Its alot of work and time! Think I'm gonna go take a couple more of those pills. Thanks again