Disco 2 Cruise control and horn fuse!

Your thinking is logical. The horn and cruise control(cc) share the same fuse. The cc supply is through the horn relay coil winding. If the horns or the horn button circuits take too much current they'll take the cc out.

I'd start by removing the outlet cable from the horn relay and see how you get on. That will eliminate, or otherwise, the rotary coupler and horn button circuits.

I'll e-mail you the relevant bits of the circuit diagrams.

Thinking further on this ....

The problem must be on the output side of the horn relay. A short anywhere else will just energise the horn relay and make lots of noise.

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Thanks for that - it's starting to make sense now. What I'm planning to do is disconnect horns and remove the relay, and then check for short circuits on that. If that's clear, I'll then try the horns one at a time and see if the problem is internal to a horn. I suspect that this is the case, as when I did try the horn, it made a very weak noise before I realised that the fuse had gone again.

Could also be a faulty relay I suppose?

Thanks Graham.

Thanks for that - it's starting to make sense now. What I'm planning to do is disconnect horns and remove the relay, and then check for short circuits on that. If that's clear, I'll then try the horns one at a time and see if the problem is internal to a horn. I suspect that this is the case, as when I did try the horn, it made a very weak noise before I realised that the fuse had gone again.

Could also be a faulty relay I suppose?

Thanks Graham.

Duff horn is my thinking. Try another.

Lee D

I doubt it. I had the same problem on my Disco. Turned out to be the horns. The problem went away when i changed them. I suspect they have been filled with water and mud at some point. I guess that caused a short in them. I didn't investigate it any further. Just happy to have my horns and cruise control working without blowing fuses.

- Lars

probably find one horn works OK, the other just clicks and pulls a huge ammount of current, so the fuse blows. Other than the cost (of fuses and holders) I can never understsand why twin horns don't have seperate fuses.

Dave B.