Horn Life

domtoni · 09-11-2007, 10:30 AM

Gang,

I bought new horns for my 69 911e last year, and my horns do not work.

We replaced the steering wheel contact, the horn relay.

The guy doing the job said the horns were bad. I don't disagree, but I can't imagine that two new horns, one year old, are to be tossed.

Any words of advise, recommedations etc?

Best
Dom

Rot 911 · 09-11-2007, 10:40 AM

Why don't you just pull the horns out and connect the two terminals by wire to your battery? That will tell you if the horns are good.

domtoni · 09-11-2007, 11:24 AM

Thanks Kurt.

domtoni · 09-11-2007, 11:24 AM

Thanks Kurt.

domtoni · 09-15-2007, 07:08 AM

Guys,

Here is my last post on the subject:
http://forums.pelicanparts.com/porsche-911-technical-forum/366505-horn-life.html?posted=1#post3473432

This is the latest:

The horns in my car don’t work. The new units, less than one year old, appear nto have burned out. I understand Porsche horns are no longer very good.

So, what did we do:
- changed the horn relay – no change the original and the new unit still click
- put a wire between the power socket and the horn beep socket and no noise
- installed a new horn switch
- we measured the current at the horn + connection, and it read a constant 13 VDC without depressing the horn button
- when depressing the horn button, power at the positive terminal drops to 0 VDC
- no changes to the wiring were made (or so we believe after the front suspension panel was replaced)
- put a Joe Lucas horn onto the circuit and it immediately started to beep

We don’t understand why the horn:
- isn’t continually beeping
- why the circuit seems to be working in reverse

New horns are on the way.

Anything else we should be aware of? Anyone have a similar experience and what solved it? I need the horns to pass the MOT.

Thanks and Best

ossiblue · 09-15-2007, 07:40 AM

This is just a guess based on what you've done so far but it could be the wiring to the relay is reversed. My understanding is that depressing the horn button grounds the relay which then will switch the power to the horn. What you describe does just the opposite and that's why a good horn sounds immediately when you connect it to the wires under the fender.

"- put a Joe Lucas horn onto the circuit and it immediately started to beep"
"We don’t understand why the horn isn’t continually beeping"

Not too clear on the above. When you hooked up the Lucas horn, did it just beep once and quit, beep intermittently, or was it a continual sound?

domtoni · 09-15-2007, 01:45 PM

Ossiblu,

Your analysis is what we concluded. The circuit seems like a normally closed one, with the horn activating when the button is depressed (opening the circuit).

All we did was touch the Joe Lucas horn up to the postive and negative wires, and it made a quick burst while the wire was attached.

We did not leave the wires on for long.

Only problem with reversing the leads into the relay, they were not touched.

Another issue, the batteries were changed about the time the horns went dead. The car has a few leads that ground on one of the negative terminals.
All wires are attached as before hand.

Any more ideas?

Best
Dom

HarryD · 09-15-2007, 04:13 PM

Dom,

See my response to your other post, but from what you are saying, it may be that someone has connected the wire that powers the horn to the normally closed point on your relay (number 87a) instead of the normally open point (number 87).

Are you using untouched stock wiring or has it been "worked on" by someone?