harveyf

I'm trying to get my neglected $1000 1984 944 ready for the state safety inspection. I'm struggling with the horn. I have ruled out most of the usual suspects in that I can get it to "toot" by applying an external ground lead to the wire that attaches to the back on the steering wheel pad that you push on. So I have ruled out everything from there forward, including the circular contact ring on the steering wheel hub and the associated stationary contact, relay, horns, etc.

On the steering wheel hub itself, when installed, what I am missing is a good ground path from the 3 brass bolt heads back to battery ground. None, nada. And I am pretty sure these bolts have to be grounded in order to complete the ground to the relay when the steering wheel pad is pushed.

Maybe I'm wrong but the circular contact ring is dedicated to the circuit back to the relay, right? And there needs to be another ground path for the brass bolts on the steering wheel, right?

So I am interested if anyone knows for certain what the factory scheme is for providing a ground path from the 3 brass bolts on the hub?

I closely inspected the key lock bracket, the turn signal assembly, and the wiper assembly for any evidence of a missing wiper or what have you that might be the ground path but didn't see any.

I have checked for continuity between the hub and the steering rack. There is none and frankly, with all the moving joints, would be mildly surprised if someone said that was the design ground path.

I have searched the archives for "horn ground" and "ground for horn" and got no hits. Just "horn" or "ground" gives too many hits.

Any advice would be appreciated.

This is the Silver Car on my website. The good news is that I took the car on it's maiden voyage after many months in the shop and everything seems to be in pretty good shape, except for the water hose that I cut down on the alternator pulley Hell, it was so cold Sunday I'm not sure the car really needed any coolant!

Paul Waterloo

I believe you are referring to a pre-airbag car. Where I am not completely familiar with this type, I did have a steering wheel from one. It just has one wire on the wheel, which is only for +12 VDC for the horn. I believe the ground path is the steering wheel to spline connection.

In the case of airbag equipped cars, the same is true, however, the clock spring has three total wires, one for +12 VDC for the horn, and two dedicated wires for the air bag. It grounds through the steering column chassis.

I just put a newer steering wheel in my 968, and the newer cars have four wires, three as listed above, and the fourth is a dedicated ground wire for the horn. This was out of a 90's 911.

So you are looking for a ground path between that goes through the steering column. Can you post some pictures?

Ky944TurboNewbie

I have an 86, and the ground for the horn is through the steering rack to the front axle cross member.

Paul Waterloo

One last thing....did you do a continuity test across steering wheel horn switch? Make sure the switch is closing when you press it.

harveyf

That makes the most sense but it also creates some problems. I do not have a ground path through from the steering wheel hub to the steering rack. With 2 u-joints and a rack/pinion to go through, it seems like a tortuous path.

Yes

Yes, agree. The problem is with the ground path after the horn switch.

odonnell

I was told that the one wire that attaches to the horn was actually the ground, I may have been misinformed however.

When you take the wheel off, the screws holding the steering column levers switches (i.e. wipers, brights, etc) on actually the grounds for those controls. Maybe you can use those? Unless they also follow the same ground path

Paul Waterloo

Yes....I agree with above, try grounding the switch assembly and see if the horn works. If it does, you can just run a new ground wire if you'd like to the front left foot well, you'll see posts with brown wires.

harveyf

The function of the "horn button" is to ground the horn relay. So everything there is a "ground" path from the relay with a Momentary Closed switch, ie the horn button.

If the ground path is supposed to run through the column to the steering rack and mine is open, I may just opt for a "kludge" to get past inspection.

Akerlie

On my 924 there is a steel rod with a copper ball on the end of it that is fastened by one of the nuts on the firewall. The copper ball lies against the steering column (on the engine side of the firewall) and gives ground to the horn.

harveyf

Very interesting. I'll have to check for something like that. May be part of my "kludge"!

kludge
klo͞oj/
informal
noun
noun: kludge; plural noun: kludges; noun: kluge; plural noun: kluges

1.
an ill-assorted collection of parts assembled to fulfill a particular purpose.

Akerlie

Yes, check it out I have been searching through the PET but can´t seem to find the rod :/ If I remember correctly it is one of the brake booster bolts that fastens the rod to the firewall.

Anyway it should be easy to make out of some steel wire. On my car the copper ball touches the steering colnum 1/2 to 3/4 of an inch from the firewall.

Butters944

Ky944TurboNewbie is correct.

The one wire that connects to the horn is the POWER. The steering hub is the ground. There should be a small brown wire from the front crossmember to the steering column.

Yes, it may be a torturous path, but it IS the way it works. I know this because I've dismanntled everything in my steering hub area before, and also when I had that wire from crossmember-steering rack disconnected my horn no longer was grounded.

Not sure why this is becoming such a complex thread haha.

The entire steering wheel hub is grounded via the steering column to the crossmember.

Anything metal on the steering wheel is grounded via its connection with the big nut holding the wheel to the column.

Akerlie

"The entire steering wheel hub is grounded via the steering column to the crossmember."

It does not make any sense to ground something through bearings.

But you are right that the rack and crossmember are grounded. That is done to prevent corrosion and interference.

harveyf

Well, sorry, but when I check the resistance from the splined steering column at the hub to the rack I get like 4 megaohms. It is not a ground path, at least not on this particular car. So I'm looking for alternatives.

Paul Waterloo

I just recently did some front end work on my car, was looking at the pictures and I think I found the ground wire. Good to know that it is the ground path for the horn (not anymore on my car as I put in a new steering wheel). It makes sense why this is needed as the rack has two rubber bushings that would insulate the rack from cross member.

Hope this helps!