[97Firechicken]

I have a 97 Firebird with V6 we have owned since new. It now has 155,000 miles on it. Horn doesn't blow when you push on steering wheel cover. It does work to signal that the car is locked. I have checked both fuses and even replaced the horn relay under the mat. Have also had issues with random power window not working, turn signal not working and the radio cutting in and out.

I read the excellent posting by GaryDoug about the BCM PC board. I am wondering if this is the problem or is the horn problem in the steering wheel wiring/horn switch. Since the horn blows with the door locking, I am suspect of the steering wheel. The steering wheel has the radio controls etc on the wheel.

It may be that I have two issues, the BCM board and the steering wheel. Any help would be appreciated. I am beginning to think the car is haunted!!!

 

[sea dog]

The only control of horn by bcm is when you lock the doors. The horn button is the standard wiring that most horns use.

Let me explain how horn works. Horn itself has a ground wire to body. It's power comes from points of horn relay. Other side of points is where power goes into relay.

The points of relay are controlled by the coil part of rely. One side of coil gets power, the other side of coil is a ground connection.

The ground goes through a switch, which in horns case is horn button. When you push horn button, the switch closes. Ground is then applied to relay coil. This energizes coil and magnetic field closes relay points. Horn blows.

When you lock doors, the bcm provides this ground to relay, horn blows, then bcm discontinues ground and horn stops.

Your problem is the horn button is no longer making contact so ground is not being sent to relay coil. Horn doesn't blow when you press button.

The contacts are in the steering column, so you would have to partially disassemble the column and get new parts to fix. Or you could download the 96 service manual, look at the horn wiring diagram. And hook up a manual horn button which would provide the ground for the horn relay coil.

96 manual in 4th gen tech section.

 

[97Firechicken]

Thanks Sea Dog, I will take the steering wheel off and look at the wiring and the switch/contacts for the horn. I didn't fully understand the involvement of the BCM. Good explanation...

thanks again,

Unk

 

[97Firechicken]

Took the Air Bag off the steering wheel. Pushed on horn contacts to blow horn, nothing. Then noticed that the red and yellow wire going to horn ring do not appear to be locked into the horn ring sleeve in the steering wheel. I can't seem to get it locked in to the tube in the steering wheel. When I look into the hole in the steering wheel, I see the plastic tube but it appears to have a white plastic piece partially blocking the horn ring. Also the outer tube where a locking slot should be looks like the piece that makes the slot is broken off so it won't lock. Is the horn ring a replacement item? Any help on this would be appreciated.

I plan to pull the steering wheel tomorrow..

Here is picture of my switches and the contact spring and wires

 

[sea dog]

The white plastic piece with spring and metal rod is what makes contact. It's been a long time since I've taken apart a steering column, so I don't remember how it fits.

With all the discontinued parts for our 4th gens, I think you'd have a better chance of finding the horn contact parts on ebay. They have many discontinued items for 4th gens.

Also download the 4th gen parts book from 4th gen tech section. It will help.

Looked at a pic of column and there should be a plastic piece that extends out for horn contact assembly to fit into.

The mostly plastic turn signal cancel cam assembly has the metal horn contact ring and the plastic extension that horn contact fits into.

Found a pic of turn sig cancel cam assembly that can upload. Here it is. It's the 2nd pic on page..

I have 2 different pdf files on GM steering column rebuild I can send you if you want them. PM me with an e-mail address to receive.

 

[97Firechicken]

Many thanks for all your help Sea Dog. I was up in the middle of the night and got on the internet for awhile and found the part. It is called a Turn Signal Cam and believe it of not it is a Dorman "Help" part and the local Orielly's had one in stock. It is Dorman 83232. It is for the tilt column. It had been a long time since I had the column apart and at that time it was to install a new ignition key with the passkey assy. I had made a tool to help compress the spring out of a flat piece of aluminum. I should have remembered what it all looked like, but unfortunately a lot of water has gone under the keel since then!!! ( 72 years have caught up with me!!!) The biggest pain in the butt is to get the ring off that holds a plate on top of the Turn Signal Cam. I modified an old snap ring plier to help remove it.

It appears that the little plastic top of the locking pin slot on the Turn Signal Cam had cracked and released the spring/wires that go inside the tube. If you look real close at the picture you can see the crack. This caused the horn circuit to be open so that there was no way for the circuit to ground through the horn switches in the wheel to complete the circuit. I will take a picture of the air bag out of the wheel if it will help.

Many thanks again for your help!!!!

Unk

Here is a picture of the part.