The horns work off the purple circuit (fused, always hot, bottom fuse in the
4-way block), the horn button sends a ground via the purple/black. You
should ideally see a full 12v on the purple at all times, perhaps a little
lower when the horns are sounding but not much. If it is much less you have
bad connections in the purple circuit. If the interior lights dims
significantly when the horn sounds it is probably a corroded fuse/holder.
You should see 12v on the purple/black when the horns are silent, and
ideally a full ground when they are sounding. However steering column
grounds can be a problem, I opted to use a relay on my 75 V8 as there just
wasn't enough current available through the column to operate one horn let
alone two.
PaulH.
----- Original Message -----
From: Karl Shultz <karl.shultz@ibm.net>
To: <mgs@autox.team.net>
Sent: Thursday, April 13, 2000 5:58 PM
Subject: Missing: horn on 73 B
> Hi all, been lurking for a *long* time now while the B, sadly, stayed
> parked with a ton of ignition problems. Finally those are sorted out
> and the car is running great. Sunny day - oh, so *that's* why I bought
> it! Anyhow, I'm hoping someone can help me troubleshoot my horn - the
> last thing that needs fixed before it'll pass inspection. Here's the
> story.
>
> When I bought the car only one of the two horns worked (low note I
> believe) which didn't bother me. About a year ago I'm driving around
> with the top down and we get one of those mid-afternoon North Carolina
> thunderstorms. It starts to really pour so I pull into the gas station,
> turn off the car and put the top up. Start the car to leave, and both
> horns (low note and high note) are blaring non-stop, without me touching
> the button. So that was kind of painful driving around like that. Get
> back to house, turn off car and go inside.
>
> The next day - start car, horn isn't blowing. This is good. So I hit
> the horn button, and both horns (lo and hi) come on. Sweet!, I'm
> thinking, it's fixed. Well, not so fast. One day later, start the car
> to go to work, hit horn button...and there's nobody home at all, neither
> horn does anything. Doh!
>
> I've done the requisite checks with the test light at the pencil switch
> on the steering wheel and at the horns - nothing. Any ideas? Is there
> a fuse buried somewhere that I haven't seen yet? Any info would be
> highly appreciated - the car's been parked for almost a year now and I'd
> really like it to be legal.
>
> --
> Karl Shultz
> Tarheel Sports Car Club - www.thscc.com
> 95 Integra GS-R, STR/DSP #78
> 73 MGB, it's alive, but not legal yet...
>
>
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