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I did a search on horns and came up with alot of helpful stuff, but could not find anything on toubleshooting the wiring. Here is the story.

I bought the 04 911 c2 6spd about a month ago. Car was new with 60 miles on it. It was in the showroom for awhile and had the trunk and engine hood lights disconnected. I wonder if they disconnected the horns to prevent people from hitting the horn in the showroom?

Now Here is what I did.

1) When you press the horn pad on the wheel, the relay clicks so that circuit should be fine.

2) Checked fuse and replaced with backup fuse,no change.

3) Replaced relay with same p/n and no change.

4) Checked connections at the horns and they are there.

I know the next step is to probe the connections and need a wire diagraham for the circuit to show me terminal location and connector locations.

I find it odd that both horns on a new car would be bad, so before I pull the bumper cover I would like to pin point the problem.



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You have checked everything except the horns (and the connection at the horns). It is a simple circuit - each horn has a ground wire (brown) and the share the power wire - that is, the relay actuates both at the same time. So, if you measure the voltage at the black/yellow wire coming off the relay panel you can be assured that power is going to the horns. At that point you have no other choice than to remove the front bumper and check the horns.

Removing the front bumper is really only a 15 minute job. When you put the bumper back on just remember to not tighten the screws fully until it is aligned with the hood and fenders (sides).

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Sounds like you've spent a lot of effort trying to fix it.

Just a thought:

Why not have the dealer fix it since you are covered under warranty? If you are far from a dealer, ask the sales/service people to see if disable of horn in showroom.

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I check voltage at the relay feed contact=Good!

I pulled the bumper cover and checked the voltage at both connecters=Good!

I could not beleive that both high and low horns on a new car could be bad all at once, but they where. Called my dealer and he gave me 2 new horns and said not a uncommon problem. Hooked them up and Bingo, both horns work.

Used the 3rd radiator instructions to pull the bumper cover and all went well.

Half the fun of owning the 911 is working on it.



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Not to negate your efforts, but this might be a good time to upgrade your horn. I found the OEM horn to be very timid, and unlikely to get the attention of, say, a truck backing into you (ask me how I know!). On the recommendation of someone on this board I bought an Italian air-horn from Griots ($39 or so) and it made a world of difference. The install should be a cinch for you by now!

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That is "sound" advice! Someone backed into my 996 when I had the horns blaring, and I immediately ran out and got the Griots horn. There is no chance that someone will not notice me the next time.

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