Horn doesn't work- ground issue on horn button wiring.

stxdriver98544

New Member
Mar 19, 2020
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0
1
35
Pinehurst, TX
Hey guys, first post here, I know this is the 100th horn doesn't work thread I've googled just about all of them on here lol. I picked up and 88 T-top and am having some trouble with it but I've got it narrowed down pretty far.

So far I've followed the electrical testing steps on here, ran a jumper wire directly from the battery to the horns and they operate just fine.

Fuse is good.

I've picked up the foam replacement kit from LMR.

I got under the dash and checked the yellow/green wire with a test light and the blue/white (I think) wire and the test light lit up with both of those. I went ahead and replaced the relay.

This car has the cruise control removed. If I run my test light from ground and probe the purple wire coming off the horn button wiring the horns sound. I've traced this thing all the way to the steering wheel. That means the little black wire, which follows to the copper wheel behind the steering wheel with the 3 prongs, I'm not getting a good ground somewhere. Since the cruise control buttons and horn wiring are all integrated into those 3 prongs where does the 3 prong wiring ground at? I even touched the 2 copper plates directly together with the foam removed and am still getting nothing, but and like I said if I touch the purple wire with the test light the horn works. I'm stumped.
 
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stxdriver98544

New Member
Mar 19, 2020
7
0
1
35
Pinehurst, TX
Ok thanks, I'll double check it, I'm highly doubting that's it because if it was than everything else that grounds to G201 wouldn't work either. I'm going to pull the console my whole ashtray and lighter assembly are missing so they could've used that wiring to ground something else aftermarket the put in.
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
34,044
10,308
224
Massachusetts
You need to isolate where the issue is. Best place to do this is at the relay.

3 wires at the relay. Wire 40, 6 and 1. Refer to the wiring diagram


Wire 1 goes to the horns. If you unplug the harness from the relay and apply 12V to wire 1, the horn should beep. This wire is then good.

Wire 6 goes to the horn switch on the steering wheel. If you leave the harness intact, but stab wire 6 with a safety pin and then connect a wire to the pin to ground, the relay should close and horn should activate. This means that the wire from here, to the horn pad, to the firewall is broken somewhere.

If it doesn't close the relay, the relay is either bad, or you have a power issue. You'll need to check the fuse at location #16. It's a 20A fuse. Does your cigar lighter work?
 

stxdriver98544

New Member
Mar 19, 2020
7
0
1
35
Pinehurst, TX
Ok I'll run all those checks, I just replaced the relay this week so it's already out from under the dash. Probably wire 6. 20a fuse is good.

Cigarette lighters been unplugged, just the connector sitting in the console by the mirror switch.
 

stxdriver98544

New Member
Mar 19, 2020
7
0
1
35
Pinehurst, TX
The cigarette lighters been unplugged, just the connector sitting down in the console area by the mirror switch, does the lighter need to be plugged in to close the circuit, if the connector is unplugged wouldn't that be an open in the circuit?
 

90sickfox

I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
5,381
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The cigarette lighter doesn't need to be plugged in for horn to work.
 

stxdriver98544

New Member
Mar 19, 2020
7
0
1
35
Pinehurst, TX
Ok everything checks out. Wire 1 honks with 12v and wire 6 honks with 12v to safety pin and ground. Time to start tracing. I'm still honking all the way up past this connector into the purple wire just behind the steering wheel by grounding the jumper wire and using a safety pin so I know the connector is good. I'm still having to ground the jumper wire this far up though which means there's something not grounding between here and the steering wheel.
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