So my horn stopped working on my 2002 575. I made up a wiring diagram by testing all the fuse and relay connections. +12v from battery feeds the upper terminal fuse F42 the lower terminal at fuse 42 connects to pin 30 of relay R19 pin 30 is the lowest horizontal terminal in R19 box the upper horizontal terminal is pin 87 which feeds the horn compressor the upper left vertical terminal of R19 box is pin 85 and connects to steering wheel horn contact the upper right vertical terminal of R19 box is pin 86 and connects directly to battery power By jumping pin 30 to pin 87 in relay box the horn sounds. Pushing on horn button should cause relay to close contacts between 30 and 87. I swapped relays with R18 and no horn sound, so relay is good The continuity is poor from pin 85 to ground when I press the horn button on steering wheel It shows 5 M ohms. So I need to check the horn button connections. Anyone know correct method to disconnect airbag in steering wheel?
here it is Image Unavailable, Please Login It looks like the same as on a Porsche. No extra locking mechanism Just pull off, but it is stuck on there pretty good. maybe a spudger will do the trick
Steve- If you go to check the horn buttons, there are small fasteners you turn from the back through the leather to get the buttons off. Believe they were very small torx or hex, cannot remember which. My techs had to swap out a horn button on my new CF wheel because one of them was duff.
Too late for you, but I'd like to warn others doing this: Before unplugging the yellow connector on the steering column, disconnect BOTH battery cables and short these to each other, or you might end up with a very persistent airbag warning lamp on the dash.
I made that mistake on my 550. Luckily it could and was reset by someone with the right diagnostic software tool. I won't make that mistake again.
battery switch was in off position for at least an hour before I pulled that red connector so checking the horn buttons, they have continuity, 0 ohms when pressed. soI checked continuity between black line feeding horn switches and relay pin 85 and now get nothing hum?
nut was not torqued, felt like it was just snug so wheel need a good pull to come off and naturally the airbag ribbon cable unwound, i wound it back on I had to snake the airbag cable from behind gear selector housing to get it off Image Unavailable, Please Login
I need help repositioning the green post. what is it for? How does it get secured? Image Unavailable, Please Login
I now get < 3 ohms between pin 85 of relay box and the carbon brush that contacts the horn ring And is there a specific orientation for the inner tube ring
okay I see here how it goes in it appears to be a restraint to inhibit clock spring movement prior to installation and then installation of the steering wheel nut presses down on the brass tab which pushes the green post off it's transport position and allows clockspring to function as it should Image Unavailable, Please Login
Here's another view of the green post.... Image Unavailable, Please Login Good to see you're figuring everything out as you go.
so just because, I checked the continuity of the airbag cable and I have a complete short. So I looked into the connector and this has shorting pins in the connector whew! Image Unavailable, Please Login
putting everything back together short of the airbag and I have good continuity between horns depressed and pin 85, so horns should now work. The only thing I did was to clean the brass ring and correctly torque the steering wheel nut. No airbag light i have a clicking noise from the airbag connector on back side of clock ring. I will need to remove again to see what is causing that.
clicking is coming from the airbag connector moving in the top cylindrical holder. Image Unavailable, Please Login I will pull steering wheel, but this time undo screws to clock ring so it stays in place.
pulled steering wheel, then withdrew clock ring, just kinda fiddled with it, put it back in position and now the connector is not moving in holder. Sometimes I never know why things happen. Reassembled clock ring to wheel as trying to mount wheel and clock ring at same time just looked like inviting trouble. Installed steering wheel, checked horn continuity, and no movement with connector in holder. Installed bottom and top steering covers. Now I can do it by feel (small consolation) Installed airbag. reconnect battery, battery switch on start car, and reset radio and time all okay Now back to working on my XK8 which dropped two inlet valve seats. Waiting on shims from jaguar for valve gapping
