My car's horn actives every time I turn the steering wheel. What do you think is causing it to go off?
My 2000 Cirrus had the same problem.
Before I describe how I fixed mine, a warning and disclaimer:
Working on the horn switch, clock spring and steering column requires working safely with the air bag module. An airbag that goes off unintentionally can cause serious or fatal injuries. If you don't know how to handle the air bag safely, do not attempt to fix this yourself!
Symptom: Horn sounds when steering wheel is turned or with slight movement of the air bag module in the center of the steering wheel.
1. Deteriorated insulators under the air bag mounting bracket screws. (This is what caused the problem in my case.)
2. Warped or bent steering wheel or air bag module.
3. Short circuit in clock spring assembly.
4. Short circuit in steering column due to abraded or pinched wire.
5. Faulty horn relay. (Very unlikely if the horn only sounds when turning the wheel.)
How the "horn switch" works: The term "horn switch" is a bit of a misnomer because there is no identifiable "switch" as one might think. The "switch" is actually a combination of parts: The four air bag bracket mounting screws, four plastic bushings and washers that insulate the air bag mounting brackets from the screws which are fastened to the grounded steering column, four springs under the bushings and the metal back side of the airbag module. The horn wire, which comes from the horn relay up the steering column and through he clock spring, is connected to the left hand mounting bracket which is electrically connected to the back of the airbag module which is electrically connected to the right hand mounting bracket when everything is assembled. When the air bag module is pushed in, the metal back contacts one or more of the four air bag module mounting screws completing the circuit to ground and thus activating the horn relay.
1. Disconnect the negative battery terminal on the strut tower under the hood and pull the two 10 A air bag fuses from the fuse panel on the left side of the dash.
WARNING!: WAIT TWO MINUTES TO ALLOW THE AIR BAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PROCEEDING. NEVER DISCONNECT OR RECONNECT THE AIR BAG MODULE ELECTRICAL CONNECTOR UNLESS THE NEGATIVE BATTERY TERMINAL HAS BEEN DISCONNECTED FOR AT LEAST TWO MINUTES. FAILURE TO HEED THIS WARNING COULD RESULT IN UNEXPECTED DEPLOYMENT OF THE AIR BAG RESULTING IN INJURY OR DEATH.
2. Loosen the two torx head screws on the back of the steering wheel that secure the air bag module to the wheel. The screws are captive in plastic retainers, so don't try to remove them.
3. Remove the air bag module, pull out the connector lock and disconnect the air bag module connector.
4. Place the air bag module on a flat surface connector side down away from where you are working.
5. Locate the four air bag mounting bracket screws. Look for black gritty debris around the screw heads and inside the steering wheel. This is an indication that the top insulating washers have deteriorated allowing the mounting brackets to short out to the screws.
6. Now reconnect the battery negative lead and do the following tests:
a. Move the left hand bracket slightly. If the horn sounds, then the top side insulating washers are either gone or deteriorated. If you want to test the right hand bracket, you will need to connect a jumper wire between the brackets. If one washer is cracked or missing, it is likely they all are.
b. Disconnect the horn wire from the left hand bracket. Start the car and turn the steering wheel to the stop in both directions. If the horn still sounds, then you have either a bad clock spring or a short circuit in the steering column.
The repair if the insulating washers are bad:
The official Chrysler repair manual says to replace the steering wheel (about $260); however, there is a cheaper solution.
1. Remove the four air bag bracket mounting screws, bushings, springs and the two brackets, paying careful attention to how they are assembled so you can re-assemble them later.
2. Clean any debris, dirt and grease from the brackets and undersides of the screw heads.
3. Purchase or fabricate some thin insulating (plastic) washers to replace the ones that deteriorated, which unfortunately you cannot buy from Chrysler. I insulated my brackets and screws with kapton insulating tape plus some very thin plastic washers I cut from some blister pack packaging scrap (probably clear polystyrene). This plastic is very thin, but still is pretty tough. Some hollow punches are handy for punching the holes and making nice round washers, but you could probably do it with small scissors or your wife's scrapbook punches if you are careful.
4. Reassemble the air bag mounting brackets to the steering wheel placing the new insulating washers and/or tape between the screw heads and brackets.
5. Reconnect the horn wire to the left hand bracket and move the bracket around a bit. If the horn doesn't sound, then you likely have fixed the problem. Once again, to test the right hand bracket, you need to jumper the left and right brackets together.
6. Disconnect the negative battery lead and wait at least two minutes before proceeding to ensure the air bag capacitor is discharged.
7. Reconnect the air bag connector to the air bag module and insert connector lock.
8. Reassemble the air bag module to the steering wheel.
9. Reconnect the negative battery lead and test the horn. It should blow only when the air bag module is pushed in. Start the car and turn the wheel to both extremes to test the repair.
If the horn sounds continuously, then the washers you put in are two thick causing the air bag module to rest on the screw heads.
10. Turn the car off and reinsert the two 10 A air bag fuses, then restart the car and make sure the air bag light comes on briefly then goes off.
Hope you find this helpful.
Aug 31, 2010 |
2000 Chrysler Cirrus