horn not working 1987 911

[ace123]

Hi,

The horn in my 1987 911 is not working. How do I go about troubleshooting it and fixing it? Is there a fuse for is somewhere? That would be the simplest to check I guess.

Hey - this is my 2nd post to the forum

Thanks!

[Driver8]

Ace the fuse panel in an 87 is under the front hood on the drivers side backing up the front fender. It is a black rectangle shaped box. On the outside there should be a listing of the fuse positions. I would start there.

Aaron

[ChkbookMechanic]

Check the horn relay in the fuse block to see if you hear it clicking when the horn button is pressed. If it doesn't click you can check the horn button and see if that is working and then clean the relay contacts. If it still doesn't work, check the horns themselves. Then of course, if all those seem to work, trace the wiring and see if something is wrong with that.

[KFC911]

Welcome aboard! If you can't get the horn to work, you can very quietly just go "eeek eeek". I'm almost embarrassed to use my horn, a blip of the throttle is a heck of a lot louder with my sport muffler and "mucho mas macho"

[masraum]

Originally Posted by KC911

Welcome aboard! If you can't get the horn to work, you can very quietly just go "eeek eeek". I'm almost embarrassed to use my horn, a blip of the throttle is a heck of a lot louder with my sport muffler and "mucho mas macho"

Weird, the horns in my '88 seemed fine. There were two and so they sounded normal. Miata's come with one horn, and one by itself sounds really wimpy. It's the dissonant notes of two horns that really get attention. Maybe only one of yours is working?

[KFC911]

Originally Posted by masraum

...It's the dissonant notes of two horns that really get attention. Maybe only one of yours is working?

Good point, and one I hadn't thought of...I'll have to check them both out, thanks!

[ChkbookMechanic]

Originally Posted by masraum

Weird, the horns in my '88 seemed fine. There were two and so they sounded normal. Miata's come with one horn, and one by itself sounds really wimpy. It's the dissonant notes of two horns that really get attention. Maybe only one of yours is working?

I found the Stebel Nautilus air horn to be better than even the two 911 horns. Nothing says watch what you're doing dumb driver like a 139db compact air horn.

[ace123]

I check out the fuse box and all the fuses looked good. There was no doco on which fuse goes to what. I looked it up in the owners manual and it said to contact the dealer. Does anyone have a diagram for future use?

Also, is the horn relay in the fuse box as well? Which one? Thanks!

[crustychief]

I have an air horn, sounds like a lambo (horn)
Not sure about an 87 fuse location. It is probably a good idea for you to get a Bentley manual for your car as well as "101 projects for your 911" available from our host. Both books are awesome by themselves, but together they are like Chuck Norris and Mr "T" having a beer at a kickboxing match. Good luck with the horn

[jeff1hughes]

If you trouble shoot and find that the horns need replacing, let me know - I have a set of OE Porsche horns I'd like to sell - new in box.

[ChkbookMechanic]

The horns don't have a fuse in the fuse panel, they are attached to a relay. On an 87 i think it is 4th from the front of the car. To confirm it, have someone press the horn button on the wheel while you are next to the relays. If one of them clicks that is the one.

[wnsgc]

In my 85 911, I have a problem with the horn working intermittently. Apparently there's a copper sensor behind the horn panel that gets corroded over time and needs to be cleaned. Not sure if that's it, but you may want to check. You can pull the horn off, carefully, but be careful as a wire is attached to the steering wheel. Then look at the sensor.

[ace123]

I'll check the relay in the morning as you stated earlier Sounds easy enough. I hope it is as simple as that.

[KFC911]

Maybe this will help:

Looking for Gremlins in a Carrera....

[ace123]

Are all the black relays the same? Are all the red relays the same in my 1987 911? If so, I could swap some around and see if other things fail and/or work. The other thread was kinda helpful, but there was some conflicting information

Can someone take a pic of their fuse box panel diagram info and upload it? I have no picture on my panel. I'm guessing it was replaced at some point. I wonder where I could find one.

Thanks!

[pozee]

You should have 6 relays above the fuse panels. #4 is the horn relay.

If you are facing your '87, the horn relay is the 4th one from the rear of the trunk (The 3rd one from the front of the car).

[ace123]

Great! I found it.

I got this from the other thread and I validated it on my 87 911

Now my Bentley has them numbered 1-6 (with 0 being unused) from back to front:

0 - unused
1 - Footwell blower motors
2 - Oil cooler fan
3 - Cruise control
4 - Horn
5 - Fog lights
6 - A/C condensor blower

I swapped the blower relay with horn relay. The heater blower worked both times and the horn didn't work at all. To validate that I pulled the correct one, I pulled the heater blower and tried the blower and it didn't work.

At this point, I validated that the relay for the horn is definitely working properly.

So what is next - horns?

How do I check the horns? Are they right next to the battery?

Thanks!

[ChkbookMechanic]

Horns are under the passenger side fender at the front of the car. To test them I'd take them out and then run 12v to the pos terminal and ground the other.

[ace123]

I knew I shouldn't have listened to my non-porsche owner friend about the horn placement. In any case, do you think the horn is the next simplest thing to test out? Removal seems difficult. What about running a couple of wires to them. Is the 12v that you are talking about the positive lead of the battery or some fuse somewhere?

Thanks!

[ChkbookMechanic]

It isn't hard to check them.. you can just run a wire from the pos. terminal on the battery to the horns. Just unplug the positive lead to the horn and make contact to the horn spade connector. The brown wire is ground.