1993T wagon. Old horns corroded and not working. Put in new ones… just a chirp (insufficient current getting through), not working really. Checked the buttons on the steering wheel..seemed ok. Jumper cable from the black/blue wire in the steering wheel to a good ground in the engine bay and the horns work fine.

Cannot find a circuit diagram with the black/blue lead. Can I assume the black/blue wire from the horns is continuous to the steering wheel area? If so, how is the horn button grounded? The jumper lead from the black/blue connection to the steering column provides the same 'chirp' but no real noise. Am thinking the steering column is not grounded properly, but do not know where to look.

I am flummoxed.
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1993 940T wagon

If you have done any work inside the drivers side of the dashboard recently, remove the access panel on the top of the steering column and confirm that the little connector for the wire that runs up to the horns has not been tugged loose (or loose-ish) from the spade lug on the slip ring assembly.

I failed state inspection 2 years ago because of that connection--installing the instrument cluster a week before had snagged the horn wire and tugged it just enough that it was loose on the spade resulting in no horn 95% of the time.

and if you go chasing other faults, here are the relevant pages (90 & 91) from the green book to a 1993 940:




I hope they are legible enough for your purposes...

FYI, connector C2 is buried WAY THE F*%# up in the left hand side of the dash. Unless you show a lack of continuity between the connector at the horn and the connector at the slip ring, don't go chasing that connector.

john

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1989 245 245K / 1993 945 131K

SOLVED!!

The root of the problem seems associated with my choice of horns. I used a couple of fiams which were for bmws- they were not new.
I took apart switches and cleaned them up…put anti ox on all connections within the steering column, behind the air bag.

The horns worked fine when checked using an external 12v source (a charger) but did not work in the car……until that is I fired up the engine. Now the horns work fine.
So the horns do not work with the ignition turned on, but do work with the engine running.
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1993 940T wagon

thanks for the tip on C2. I do indeed have continuity from the horn to the slip ring. in fact I do have a circuit, just not enough power...which makes me think that the grounding of the steering column is suspect. If I connect a jumper between the slip ring and a good ground the horns work.

andrew
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1993 940T wagon

Hello,

Referring to the diagram by dinomartino, component 6/1 is the windshield wiper motor. If your wipers are working, the horns are getting power. Check the grounding path.

Hope this helps,
Amarin.

trying to locate ground path for steering column.
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1993 940T wagon

https://www.brickboard.com/FAQ/700-900/ElectricalLightingHorns.htm#HornButtons

Blue-black wire goes to a collector ring which in turn has a red wire to the horn buttons where the grounding occurs. I'll bet your horn buttons are corroded.

steve, now I think about it, I removed one of the horn buttons and shorted the two connections….same result, just a chirp from the horns……so I do not think the issue is the horn switches.
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1993 940T wagon

There is a round collector ring in the steering column to which the black-blue wire runs. Current goes from there to the horn buttons via a red wire. Check that ring and wire. The horn buttons ground through the steering column itself. You may want to kludge a separate ground wire to the column to test this ground path

thanks again to the responses. The circuit diagram was better than the one I had.
I believe the issue is the grounding of the steering column because as you put it "a kludge" from the horn button connector to a good ground makes the horns work (the current goes through the collector ring before getting to the horn switch).
I have opened up the area (real PITA) by removing the knee bolster plate but still am unable to see where the grounding of the steering column occurs.
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1993 940T wagon

that is helpful.
I did look at the FAQ first, however I thought it unlikely that both horn buttons would fail at once (they seems to be wired in parallel).
When I do depress the brass plate they do get very hot, even though I just get chirping from the horns, so there is circuit.

Could not see how to take apart the horn buttons. Do I attack them from the brass plate side and pry off the brass plates?

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1993 940T wagon