Find the horn wiring diagram on bmwteka.com.

 

Great site. Studying it now, hopefully I can find out whats happening.

If the relay was pulled off, then how did it got power to click?

I hooked up a wire from battery pos and neg to the relay. I think it was pins 85 and 85. I have it written down somewhere but dont remember right now exactly which pins.

 

I pulled the relay and jumped pins 85 and 86 and relay clicked.

If the relay was pulled off, then how did it got power to click?

 

I pulled the relay and jumped pins 85 and 86 and relay clicked.

This to me is like short out (jump) pin 85 to pin 86; not a good description.

I hooked up a wire from battery pos and neg to the relay. I think it was pins 85 and 85.

This to me is like applying 12v power across pin 85 to pin 86, and yes it will cause the click because the relay coil was energized.

Your problem is in the steering wheel that the horn button is not shorted to ground when pushed, probably the split ring is bad.

 

This to me is like short out (jump) pin 85 to pin86; not a good description.

This to me is like apply 12v power across pin85 to pin86, and yes it will cause the click because the relay coil was energized.

Your problem is in the steering wheel that the horn button is not shorted to ground when pushed -- probably the split ring is bad.

Sorry. I'm not familiar with the exact terms. I thought jumped was the right term. Ive been reading lots of info on this and this words was used.

I read somewhere that pin 30 gets constant power, my car has that, and pin 85 or 87 gets power when the key is in acc position. I did this test and i didnt get power to any pins besides pin 30. Does that help isolate the problem?

Also do you have any suggestions where I can read how to test what is bad in the steering wheel, whether slip ring, or horn button. I cant find info on how to diagnose the horn related parts in the steering wheel.

Regarding slip ring, does the fact taht all the buttons work on steering wheel (radio volume and cruise control) help identify the problem?

My airbag light is on as well.


Thanks for the advice.

 

There's a couple of different versions (unsure what year your car is) of the wiring.
Power is always available at the relay when the car is on. Pressing the horn contact in the steering provides a ground to the horn relay.

The ground is from the steering column, through the horn pad, through the "volute spring" (slip ring) and onto pin # 85 of the horn relay.

I would first check by leaving the relay installed, and CAREFULLY supplying a ground to pin # 85. Does the horn work?
If so, then check if pressing the horn pad brings a GOOD ground from the pad, through the volute spring and onto pin
# 85.

BMW WDS Online

bmw wds online for all browsers

bmwteka.com

 

There's a couple of different versions (unsure what year your car is) of the wiring.
Power is always available at the relay when the car is on. Pressing the horn contact in the steering provides a ground to the horn relay.

The ground is from the steering column, through the horn pad, through the "volute spring" (slip ring) and onto pin # 85 of the horn relay.

I would first check by leaving the relay installed, and CAREFULLY supplying a ground to pin # 85. Does the horn work?
If so, then check if pressing the horn pad brings a GOOD ground from the pad, through the volute spring and onto pin
# 85.

BMW WDS Online

bmw wds online for all browsers

bmwteka.com

How do I check if it gets a ground? Can I use a multimeter?

Pin 30 has power. Fuse 5 and 55 have power too.

Update: I checked thr wire diagram and it shows that wires to the relay go through fuse 5 and 55, one through each. If my fuses are fine and they get power but the relay does not click when I press the horn, would that mean I have an issue in between the fuse and thr relay?

 

With the relay removed (read your post too fast) if you jumper across pins # 30 & 87 in the relay socket. Does the horn come on?
Does pin #30 have power?