When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've read through all of the posts about horn issues. My car was sitting for a long time put a new battery in everything is up and running again. But the horn will not stop. I pulled the horn relay out so it would stop. I've seen posts about the switch that's behind the airbag going bad or sticking. Is there a way to unplug that switch before I go down the road of taking the steering wheel apart just to make sure that's the issue? I haven't seen anything about it being done that way.
I've read through all of the posts about horn issues. My car was sitting for a long time put a new battery in everything is up and running again. But the horn will not stop. I pulled the horn relay out so it would stop. I've seen posts about the switch that's behind the airbag going bad or sticking. Is there a way to unplug that switch before I go down the road of taking the steering wheel apart just to make sure that's the issue? I haven't seen anything about it being done that way.
One way would be checking for a ground at relay 36 coil socket (horn relay) in the underhood fuse box. If the membrane is closed/shorted, it will have a ground.
So question. When I first stRted the car only 1 horn was on, then the second kicked in afterwards.
I'm not sure I understand the concept of the ground. Wouldn't it still have to be charged from the fuse on the positive side and that constant circuit Would cause the circuit to be complete?
Or does the switch close the ground side? Not sure I understand the concept
So question. When I first stRted the car only 1 horn was on, then the second kicked in afterwards.
I'm not sure I understand the concept of the ground. Wouldn't it still have to be charged from the fuse on the positive side and that constant circuit Would cause the circuit to be complete?
Or does the switch close the ground side? Not sure I understand the concept
Sounds like you need to take it to a good auto electric shop. Good luck
Thank you...so I checked the terminals at the relay. The two terminals closest to the center of the car have a ground. Does that mean the horn is shorted? Unplugging the horn removes the ground at the terminal closest to the windshield. Bad horn or do I need to look at the switch?
There is a small schematic on the side of the relay, the corresponding numbers are also on the bottom of the relay next to the terminals. I will correlate the relay as you have described.
87 - If you have a path to ground here that goes away when you unplug the horn. The path to ground will also go away if you remove the horn fuse #11(with horns plugged in).
86 - Ground provided by the steering wheel membrane switch or the BCM (edited)
85 - 12 volts at all times
30 - 12 volts at all times
Last edited by lucky131969; Jan 29, 2025 at 07:06 PM.
How do you have your test light connected ??...to see if the wire from terminal 86 is shorted to ground OR the membrane contacts are closed connect the test light to battery POSITIVE and probe 86 (to check if that is the correct terminal the terminal caddy corner to it will have 12 volts at all times...that is coil side feed)...if the right terminal is identified and the test light illuminates you will have to remove the airbag and remove the red wire and see if the test light goes out...watch the video...if it is still on the wire is shorted to ground somewhere...if light goes out the horn membrane contacts are closed...you can check between the red and black wires with an ohm meter...if there is continuity the membrane is bad....did you try swapping the relay ??...BTW, this can also be the BCM's horn relay control (horn sounds when you push the panic button) driver failed closed...in that case you can remove the C1 connector from the BCM.
Thank you! That is exactly the information that I needed. Now see how this circuit and relay work. That should give me enough to track this down. Thank you again
No problem so as I said this can be 3 things…BCM relay control driver failed closed, wire from fuse box to horn membrane shorted to ground or the membrane contacts failed closed…it’s not hard to remove the airbag…just be sure to disconnect battery negative when working on it…years ago my 2001 horn was not working…disconnected the red wire as shown in video and just cleaned it up some some emery cloth…didn’t “look” bad was enough oxidation to cause it not to work.
BCM C1 connector is the middle connector...this can be 4 things and not 3 as I mentioned...forgot the load side contacts of the relay (87 and 30) welded shut.
BCM C1 connector is the middle connector...this can be 4 things and not 3 as I mentioned...forgot the load side contacts of the relay (87 and 30) welded shut.
Right, but he posted he has a path to ground at 87 and 86.
Right, but he posted he has a path to ground at 87 and 86.
How is his test light connected...to ground or B+ for checking all 4 of these terminals ??...if connected to ground the light will illuminate on 30 and 85 (load and feed side power)...if probing with test light still connected to ground and testing 87 test light will not illuminate unless test light is connected to B+...the test will now illuminate because it is finding a ground through both horns to G102...if testing terminal 86 and test light still connected to ground test light will not illuminate because it is looking for a POWER not ground...there is no power there...is his test light connected to B+ to check 86 ??...whenever you say a "path to ground" test light has to be connected to B+.
How is his test light connected...to ground or B+ for checking all 4 of these terminals ??...if connected to ground the light will illuminate on 30 and 85 (load and feed side power)...if probing with test light still connected to ground and testing 87 test light will not illuminate unless test light is connected to B+...the test will now illuminate because it is finding a ground through both horns to G102...if testing terminal 86 and test light still connected to ground test light will not illuminate because it is looking for a POWER not ground...there is no power there...is his test light connected to B+ to check 86 ??...whenever you say a "path to ground" test light has to be connected to B+.
How is his test light connected?.....well the OP checked two terminals with his test light and it illuminated. Had he been connected to B- it would not have illuminated at 86 and 87. He documented this in two images in post #7....did you see the pics? The path to ground exists independent the test light. The test light only verifies the path provided it is connected to B+. I explained the connections in post #8, but I did forget the BCM ground input.
Not sure where we are apart here.
Last edited by lucky131969; Jan 29, 2025 at 07:21 PM.
Okay so I have the test light connected to the B+.
Both 86 and 87 have a ground (light on).
switching the test light to the B-, 86 and 30 have constant power.
Before I remove the air bag what would I be checking in the BCM?
........ Well reading through the post above I think I answered my own question. I removed the top plug on the BCM and I still have a ground at 86 and 87. I guess that pretty much limits it to my horn membrane. I guess next step is remove the airbag.
Last edited by Johnnyv49; Jan 31, 2025 at 07:16 PM.
Ok, hook the test light to ground or battery negative…2 of the terminals should light the test light….now hook test light to B+…go caddy corner from those 2 terminals that illuminated the test light…probe those other 2 terminals…ONLY 1 should illuminate the test light…that is the circuit that goes through the horns and then to ground and will illuminate the test light. …the other should NOT and that is the terminal that goes to the horn…it should ONLY illuminate if you push the horn pad….if both illuminate you have a short to ground on the one…86 can’t have both a power and ground and I said it’s the middle BCM connector…what about 85 ??…I think you should take the car to an electrical specialist.
Horn does not turn off.
