Darn horn doesn't work
11-26-2004, 06:10 PM
#1
Instructor
Thread Starter
Darn horn doesn't work
I finally had some time to get in and see if I could get my horn to work.
A little history... When I first bought my 928 the horn worked. Then about a year ago, coming out of a parking lot, it went off for about a minute straight without me touching the button, and after that it never worked again. I don't use it that much, so I didn't look into it right awy. But, I noticed later, during other maintenance, the PO added an aftermarket air horn in addition to the stock.
I did alot of reading and still wasn't sure where to start to troubleshoot. I took a battery jumper and put the leads on the horns at the wheel well, the horns seem to work. I checked fuse 18 and it seems to be fine. I swapped the relay with another and the rear wiper is working, so I think the relay is ok. I took the steering wheel cover off (momo aftermarket) and manually touched the lead to the outer ring, still nothing.
While I was in there I went ahead and removed all the aftermarket crap (pretty extensive BTW, had two separate units with all kinds of air hoses going to about six differtent horns).
I just don't know where to start with this... Anybody have any ideas?
A little history... When I first bought my 928 the horn worked. Then about a year ago, coming out of a parking lot, it went off for about a minute straight without me touching the button, and after that it never worked again. I don't use it that much, so I didn't look into it right awy. But, I noticed later, during other maintenance, the PO added an aftermarket air horn in addition to the stock.
I did alot of reading and still wasn't sure where to start to troubleshoot. I took a battery jumper and put the leads on the horns at the wheel well, the horns seem to work. I checked fuse 18 and it seems to be fine. I swapped the relay with another and the rear wiper is working, so I think the relay is ok. I took the steering wheel cover off (momo aftermarket) and manually touched the lead to the outer ring, still nothing.
While I was in there I went ahead and removed all the aftermarket crap (pretty extensive BTW, had two separate units with all kinds of air hoses going to about six differtent horns).
I just don't know where to start with this... Anybody have any ideas?
11-26-2004, 10:10 PM
#2
Rennlist Member
Rennlist Site Sponsor
1) Pull Relay XII (Horn Relay) and check for 12 vdc on terminal 30 in the socket. If there is no voltage, check fuse #18.
2) If there is 12 vdc on terminal 30, touch a jumper between terminals 30 and 87. If the horn blows, the horns and wiring are OK. If the horns don't blow, make sure that Plug P is tightly plugged in.
3) If the horns blow with the temporary jumper, check for 12 vdc on terminal 86. If there is voltage on terminal 30 but not terminal 86, the problem is on the jumper behind the Central Electric Panel.
4) If there is 12 vdc on terminal 86, check for a ground on terminal 85 when the horn button is pushed on the steering wheel pad. If there is no ground, either the contacts inside the steering wheel hub or the wiring (brown/white stripe) between there and the relay is bad.
2) If there is 12 vdc on terminal 30, touch a jumper between terminals 30 and 87. If the horn blows, the horns and wiring are OK. If the horns don't blow, make sure that Plug P is tightly plugged in.
3) If the horns blow with the temporary jumper, check for 12 vdc on terminal 86. If there is voltage on terminal 30 but not terminal 86, the problem is on the jumper behind the Central Electric Panel.
4) If there is 12 vdc on terminal 86, check for a ground on terminal 85 when the horn button is pushed on the steering wheel pad. If there is no ground, either the contacts inside the steering wheel hub or the wiring (brown/white stripe) between there and the relay is bad.
11-27-2004, 12:48 PM
#5
Burning Brakes
Perx,
Do you have any radial play in your steering column? Is your upper steering bearing ok? Sometimes excessive play in the upper steering bearing will cause the contact that is riveted to turn signal/cruis control switch to wear or fall off.
Do you have any radial play in your steering column? Is your upper steering bearing ok? Sometimes excessive play in the upper steering bearing will cause the contact that is riveted to turn signal/cruis control switch to wear or fall off.
12-15-2004, 12:04 AM
#7
Addict
Rennlist Member
Rennlist Member
Wally,
Thanks for this. I just used it to fix my horn -- the copper spring contact under the wheel wasn't extended enough to make contact with my changed steering wheel.
Thanks for this. I just used it to fix my horn -- the copper spring contact under the wheel wasn't extended enough to make contact with my changed steering wheel.
Originally Posted by WallyP
1) Pull Relay XII (Horn Relay) and check for 12 vdc on terminal 30 in the socket. If there is no voltage, check fuse #18.
2) If there is 12 vdc on terminal 30, touch a jumper between terminals 30 and 87. If the horn blows, the horns and wiring are OK. If the horns don't blow, make sure that Plug P is tightly plugged in.
3) If the horns blow with the temporary jumper, check for 12 vdc on terminal 86. If there is voltage on terminal 30 but not terminal 86, the problem is on the jumper behind the Central Electric Panel.
4) If there is 12 vdc on terminal 86, check for a ground on terminal 85 when the horn button is pushed on the steering wheel pad. If there is no ground, either the contacts inside the steering wheel hub or the wiring (brown/white stripe) between there and the relay is bad.
2) If there is 12 vdc on terminal 30, touch a jumper between terminals 30 and 87. If the horn blows, the horns and wiring are OK. If the horns don't blow, make sure that Plug P is tightly plugged in.
3) If the horns blow with the temporary jumper, check for 12 vdc on terminal 86. If there is voltage on terminal 30 but not terminal 86, the problem is on the jumper behind the Central Electric Panel.
4) If there is 12 vdc on terminal 86, check for a ground on terminal 85 when the horn button is pushed on the steering wheel pad. If there is no ground, either the contacts inside the steering wheel hub or the wiring (brown/white stripe) between there and the relay is bad.