-
Horn stuck on
I am going to give in and need some help / pitty. Electrical was working well and even had a go cart ride a couple of weeks ago, Now the horn is stuck on whenever I power up the battery cut off switch. I had the dash on and off several times and I assume I knocked a connection loose but can't find it. The other thing I don't understand (very limited electrical knowledge) is that when I check the horn switch it has two poles. Black is ground and brown is hot (always). How do you complete a circuit with two poles + and -??
-
Tool Baron
Your horn button is stuck (in the ON position) the button completes the ground path. The reason you may see voltage on the brown wire is that (1) the button is stuck and (2) your meter is reading through the coil of the relay that controls the horn. Replace the button.
Frank
__________________________
Factory Five Racing MKIII Super Snake Replica. Cannonball Cobra Drop Trunk Box, Horn Button and other machined Do Dads.
i.e.427 Chromed Full Width Roll Bar with integrated LED Third Brake Light.
I will never forget My Buddy Paul.
-
Cobra Addict
I'd just leave it on. Think of all the attention these cars already get. You would get all the "looks".
-
Post Thanks / Like - 3 Thanks, 0 Likes
-
Steve >> aka: GoDadGo
Originally Posted by
AtlantaCobra
I'd just leave it on. Think of all the attention these cars already get. You would get all the "looks".
Best Answer Ever!
Hopefully, the horn button is the culprit....
Last edited by GoDadGo; 02-21-2022 at 09:17 AM.
-
Senior Member
Just to expand very slightly on frankeeski's response (which was 100% accurate of course) and your admitted limited electrical knowledge. Assuming you have the Ron Francis harness. Otherwise this description doesn't apply. There is a horn relay in the RF panel. When the two wires that go to the dash harness (BRN-HORN-SW and BLK-GROUND) and connected via the horn momentary switch, the ground circuit for the horn relay is completed. The relay closes, and +12 is sent to the DK GRN-HORN wire in the front harness attached to the horns which are grounded via the BLK-GROUND wire also in the front harness. All visible and can be traced in the RF Chassis Wiring Harness manual.
As stated, don't troubleshoot by measuring the voltage on the dash wires. Those are just completing the horn relay ground circuit as described. Likely your switch is defective, e.g. stuck on. Easy enough to troubleshoot. Pull the wires from the switch. The horn should go off. Touch the wires to each other and the horn should sound. Good luck.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014.
Build 2: Mk4 Roadster #7750. Sold 04/10/2017.
Build Thread
Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020.
Build Thread and
Video.
Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020.
Build Thread and
Video
Build 5: 35 Hot Rod Truck #138. LS3 and 4L65E auto. Rcvd 01/05/2021. Legal 04/20/2023.
Build Thread. Sold 11/9/2023.
-
Post Thanks / Like - 0 Thanks, 1 Likes
-
Senior Member
Just drive! Can't hear the horn over the exhaust anyway!
MK3 Challenge Car, Boss 347, Sniper 2 EFI
-
Senior Member
It could be the switch, the relay, or a short. Don't start replacing parts just yet.
Do what edwardb says about disconnecting the wires from the switch. If the horn stops, touch the wires together. If the horn blows by touching the wires together, replace the switch.
If the horn keeps blowing with the switch disconnected, pull the relay out. They usually don't fail on, but anything goes with Chinese parts. If the horn stops, replace the relay.
If it doesn't stop with no relay and the switch disconnected life just got hard and you have a short in the wiring.
-
Senior Member
You can take the switch apart and see what's sticking, when I got mine it was assembled wrong so it was on all the time, it's easy fix.
FFR8237 Donor build 89 GT , MK 4 , T5 , 17 " hallibrands 9" front 10.5 rear ,4×4 headers stainless mufflers, dual chrome roll bars, coil overs all 4,A/C and heater , soft top, 3:55 gears.
-
Post Thanks / Like - 1 Thanks, 0 Likes
WIS89 thanked for this post
-
Senior Member
Originally Posted by
john42
Just drive! Can't hear the horn over the exhaust anyway!
Haha too funny
Matt
FFR Complete Kit, Coyote, Tremec TKX, 3.73 IRS, power steering, 18" Halibrands, Wilwood brakes, Gas-N pipes + header, Viking blue color
Roadster Build Time Tracker
-
THanks for all the advice ... got home and disconnected switch - aftermarket chinese that's off amazon but even totally disconnected the horn still blows. Will try replacing the relay tomorrow. I'd love to drive it with the worn blowing but I'm still in the garage with one go cart under my belt (horn was working fine then) - getting ready to trailer it down to Ken Pike's end of next month.
-
Post Thanks / Like - 0 Thanks, 1 Likes
-
Senior Member
These things have a horn??
-
Not a waxer
Originally Posted by
mdutton11
...Will try replacing the relay tomorrow...
Don't buy a relay until you know what you have is bad. Unplug it---if the horn stops it's bad---if it doesn't stop then it isn't a bad relay.
Jeff
-
Senior Member
Automotive relays can audibly be heard clicking or at the least by feeling them. Try this..
Leave the horns disconnected so you keep your sanity. With your power on, pull the horn relay. See if you hear or feel it click in your fingers. With it out you can actually lightly make contact to recheck. If the relay is clicking when you put it in and out then you have a ground on the trigger wire… in other words from the horn switch. It doesn’t have to be from the switch, can be anywhere. Since you said it worked but had the dash in and out.. you may have pinched a wire or bent a pin in a connector when reconnecting.
If it doesn’t click.. Leave it out and reconnect the horn. If it blows again then you have foreign battery on the wire from the relay to the horn. If not then put the relay back in. If it now sounds you have a bad relay.
Good Luck
Brian
-
Relay it was!!! Pulled it and horn did not fire - took the cover off the relay and very corroded . Switched it with the one next door (fuel pump) and all worked fine. Got a new one at Napa and so far all seems to be working well. Thanks to all -if I have any more problems I will shout out. Cheers!
-
Post Thanks / Like - 0 Thanks, 1 Likes
-
Sorry - Cooling fan relay is next door. Fuel pump relay is on the opposite end.
-
Senior Member
Good job with your troubleshooting!