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Horning activates by itself

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dcarlson12
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Year and Model: 1997 850 T5
Location: Surrey, BC, Canada
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Horning activates by itself

Post by dcarlson12 » Tue Jun 12, 2018 11:07 pm

96 850 with about 126,000 km.
The horn is coming on my itself.
I guess the is a problem inside the steering wheel with the horn wire shorting or ?

When the ignition is shut off, the horn no longer sounds.

I have had to just disconnect the connectors at the horns.

I guess I have to remove the air bag and do some exploring.

I know to disconnect the battery for awhile to prevent the air bag from firing and then remove the air bag to get access.

How does one remove the air bag?

Is it likely I will just be able to reconnect a wire or ?

Thks,
Dwight



Ozark Lee
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Re: Horning activates by itself

Post by Ozark Lee » Wed Jun 13, 2018 6:12 pm

There are plastic insulator bushings that are prone to breaking. I know odometergears.com sold a repair kit for it and it is a fairly simple fix ( http://www.odometergears.com/products/V ... 0+92-97/15 ). I think there are other repair kits as well but I have had real good luck with their odometer gear replacement parts and I would suspect that the repair kit is high quality as well. I have not personally had the problem but I never use the horn either.

...Lee


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MDK
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Re: Horning activates by itself

Post by MDK » Wed Jun 13, 2018 7:31 pm

Ok D ...MDK here. Okay so disconnect the battery ... I'd do positive and negative.... let it sit for about a half hour or so to let the electrical system discharge...then... behind the steering wheel are 2 holes .. one on each side... I think you'll need a #27 torx head bit... preferably a screwdriver driver type and remove them. If you use a woman's compact mirror and a flash light you'll see what I mean. Then lift out airbag and unplug it.... difficult to unplug...use little care not to damage plug connector... and there you are...



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Re: Horning activates by itself

Post by MDK » Thu Jun 14, 2018 2:45 pm

Hey there dc12... I forget to mention that doing your repair the 850 steering column has a clam shell design... so if you have tilt steering wheel it's also telescopic... pull lever down and pull steering wheel out. Should be 3 torx type screws/ bolts loosen those up and remove upper and lower clam shell..then the 2 torx screws/bolts to remove air bag... just remember to disconnect the battery and leave sit for a while before disconnecting airbag plug connector... you may just have dirty or sticky contacts on your horn assembly.. hope this helps...
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dcarlson12
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Year and Model: 1997 850 T5
Location: Surrey, BC, Canada
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Re: Horning activates by itself

Post by dcarlson12 » Sun Jun 24, 2018 1:32 pm

Did the repair of the insulators.

After the repair, moved the car out of and then back into the driveway. As I turned the steering wheel when backing out, the horn again sounded by itself. I pressed briskly on the air bag and the honking stopped.

I also replaced the clockspring mechanism because the old one had fallen apart. ( the clear plastic had disintegrated).

Not sure if I want the wife to drive the car in case the horn comes on again by itself.

Is it possible that the hot wire for the horn can short inside the ignition switch?

Thks,
Dwight



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mrbrian200
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Re: Horning activates by itself

Post by mrbrian200 » Mon Jun 25, 2018 1:48 am

On most of these older vehicles you can bypass the switch in the steering column. This is likely the case in an '97 850. To comply with safety regulations and pass safety inspection if you are subject where you live, you can connect the wire(s) horn control wires that go into the steering column to a normally open momentary switch. The switch must be permanently and securely mounted to the dash within arms reach of the driver and clearly labeled "HORN". The diagram I have for the 850 doesn't show the horn switch circuit that goes into the steering column. You'll have to figure out whether there are two wires that would wire directly to a momentary switch, or whether there's one wire that would go to the switch (and another wire you'd have to add that completes a ground connection when the switch is pressed.

On newer vehicles the horn is controlled via CAN data and there aren't wires dropping down from the steering column that can tapped to directly control the horn: you'd have to disconnect the horn from the vehicle harness and add separate/new fuse and relay circuits.



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Re: Horning activates by itself

Post by Ozark Lee » Mon Jun 25, 2018 8:23 am

There is a procedure for re-installing the airbag that requires one side to be tightened before the other side. I can't remember the particulars but it is in the manuals and it is likely included in any instructions that you got along with the new insulators. It could be that the the horn plate was just hung up and it only needed to be popped back into place which you did when you hit the airbag.

To the best of my knowledge the horn contacts don't route through the ignition switch at all.

...Lee


'94 850 N/A 5 speed
'96 Platinum Edition Turbo
'99 V70XC - Nautic Blue
Previous:
1999 V70XC - RIP - Wrecked Parts Car.
1998 S70 T5
1996 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

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Re: Horning activates by itself

Post by rspi » Mon Jun 25, 2018 8:37 am

The collar has two T10 screws way up in it, one on each side.

Airbag screws are T30.


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