2G Inoperative horn diagnosis on 2g

The 2g's have alot of problems with the horn buttons not working. I took a few pictures and figured I'd put put something in print to go with it.

First and foremost ALWAYS check your fuses first. Check both the fuse block located just above the left foot area inside the car and check the power distribution center (fuse block under hood) for blown fuses.

I prefer to check most electrical problems at opposite ends first and then work my way towards the middle of the circuit. The horn under the left front head light (on 99RS models at least) and the switches at the steering wheel are the ends of the system. It's easier to get to the horn switches themselves rather than the horn.

So the first thing you'll want to do is disconnect the battery. -edit: Prior to doing this, make sure you have your radio code if you are still running the factory radio. In many cases, you will have to reset the radio if you disconnect the battery. :end edit--You do this to protect yourself from having the airbag go off in your face. Make sure you disconnect the battery and let the vehicle sit for about 5 minutes.

--------The airbag system is designed to deploy when the vehicle is impacted in a certain manor. In the event that the airbags are not required to deploy, the system still remains armed in the event of a second impact. The capacitors are for accidents where power to the airbag system is lost. The capacitors provide that power source to keep the airbag system in operating condition until the driver can exit the vehicle.------

After the battery has been disconnected for five minutes, you can safely remove the airbag from the steering wheel. You do this by removing the four 10mm bolts that hold it to the steering wheel. There's one bolt in each area circled below. The two red circles indicate the horn switch location and on the back side of all four circled areas you will find the bolts.

 

[Doug99RS]

Next you'll want to locate the horn wire. This is the wire that I've circled multiple times with red. The center circle shows where the clockspring wire meets the airbag side of the horn wiring. The clockspring is a component with wiring in it that is designed to allow for constant wrapping and unwrapping as you turn the wheel from stop to stop. The areas circled in that horrible green color indicate the airbag wiring.

What you will want to do now is disconnect the horn wiring. The connector is protected by a rubber sleeve. Slide it off. The connector is slimply pushed together, male in to female connectors. If you pull and give a slight twist to it the connector will seperate. I would recomend NOT letting the horn wire touch the airbag anywhere. While the horn buttons simply provide a ground path, there's no need to see if there's any extra current left on the system to deploy the airbag. Just don't be that guy.

Now that you've got the connector seperated, you can touch the vehicle side of it to the steering wheel. The horn should sound if the horn, fuse(s) and wiring is good. If your horn works then your problem is in the switches themselves. I've been looking for individual horn switches seperate from the airbag but so far have had no luck. Stay tuned for an udpate there. But that bit of diagnosis will at least let you know if the problem is these switches or not.

 

[Doug99RS]

If your problem still persists then you'll want check the horn. You can do this best by removing it. Once removed from the just under the left front headlight, attatch two wires to it. One on one pin-out and one on the other pin-out of the horn. Connect the other end of one wire to the battery positive side, connect the other to the negative. If your horn works then and you've already checked the airbag area then your problem is going to be in the wiring somwhere.

Check the power side of the horn harness. This is the green wire with a red tracer (stripe). You'll need a test light for this as well as someone else to blow the horn. Connect the clamp end of the test light to the vehicle chassis and press the pointed end in to the connector at the green/red wire. Back-probing the wire or using a paper clip to get in to the connector may work better without dammaging the connector. When probing it, have your friend press the horn button. If the test light illuminates then you've got power to the horn but your ground may be bad.

After verifying that you have power checking the ground will be easy. Clamp on to the battery positive terminal. Then put a jumper wire in to the black wire pin-out of the horn connector and connect it to the pointed end of your test light. If the ground is good then your light will illuminate. If the ground is bad, it will stay un-lit. You can either run a new ground wire for it or check the ground wire from the factory. Turbo models will ground on the right front fender and non-turbo models will ground on the left front fender area.

Most of the problems are going to be in the horn, fuse, horn switches or a bad ground. You can PM me for additional diagnostics but I doubt it will be needed.
Doug

 

[pauljairem09]

Thanks for this