E350 horn stuck on, and fix.

[philos]

Osita van was kind enough to wake the neighborhood at 5:52 am last week when her horns (hella supertone!!!) got stuck on with the temperature changes. A few whacks and some pulling on the cover made it stop while I went and made some tea and finished waking up.
Driving around town, it's gotten stuck once more this week.

Apparently the wafer thin plastic/copper combination wears through and the horns go cray. Swelling or contracting plastics complete touchy circuit, and....angry neighbors.

I had picked up a spare contact pad yesterday at the junkyard, but then I just read this thread: http://www.powerstroke.org/forum/99...-horn-contact-fix-dont-need-new-airbag-2.html

So, today or tomorrow I'll be cutting into my existing contact pad to do some silicone work. Seems to be a great solution to a common design shortcoming.
I'll keep my "new" spare in case I butcher the operation.

I'll try to remember to take pics of my hackery.

 

[philos]

Okie dokie.

Took me a few extra days to get to this...

So, I disconnected both negative terminals from the two batteries.

Went and made a snack while the airbag sat for ten minutes.

Removed up the two small plastic covers on the back of the steering wheel to remove the retaining screws. Then unplugged the two plugs and removed airbag assembly.

Took it to a flat surface to tear into, and removed the two torx screws that retain the horn contact pad. Then peel the cover back.

Contact pad comes out easy.

I used an xacto to gently slice my way in between the layers, then just slowly peeled the rest up to the top of the contact, but not all the way.

Got some nice RTV and made a moderate hash of adding more material to each of those rubbery dots with a stick.

After that cured for several hours, I used a thin layer of contact adhesive around the edges to seal it up.

Stuck it all back together and reconnected my batteries.
Aaaand, fail.
HAHAHAHA!!!
My messy dots were too much, and the contact no longer contacts.
Disconnected batteries again, had another scoobie snack, took out my new copper pillow, dropped the contact from the junkyard in, and my horn works!!! It doesn't stick on anymore. I'm confident it's not going to go off at 5:52 am again either.

But there's a new but...
My airbag light is on now. I couldn't get either of my cheap scanners to find a code. Horn works fine, so I'm not thinking it's the clockspring. I'll go by a local shop and borrow a real scanner asap.
I did change all my instrument cluster lights to LED while I was in there, so it's possible it doesn't like the low voltage of the new bulbs...
I'll find out and no, the original bulb wasn't burnt out.


Sooo, moral of story is to follow the protocol in the original repair thread if you're going to repair. Or, just replace the dang thing.

FYI, dorman makes a replacement contact pad that retails around $130 if you can't find one on another van or truck (yes, Mabel they do interchange!) at the junkyard for $12 like I did.



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[Bbasso]

I had that happen once, I just loosened the two screws (ever so slightly) that hold the airbag to the steering wheel and never had an issue again.

 

[philos]

I had that happen once, I just loosened the two screws (ever so slightly) that hold the airbag to the steering wheel and never had an issue again.

That seems... easier.