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MG Midget and Sprite Technical - Horns

I have followed Paul Hunt's advice on how to test horns, and can verify that all is wired correctly, but the horn doesn't work from the push. The steering column appears to be isolated from the rest of the car, I don't expect this to immediately believable, it's definitely in the strange but true category....

Here is a photo of the horn push without the button. The pencil in the middle brings 12v, but the copper ring has no ground except to the steering shaft. The shaft is not electrically grounded to the rest of the car!

Pushing the engine earthing strap into contact with the steering shaft makes the horn work, so this is why it worked before. But what is the permanent fix?Any suggestions on how to recreate an earth between the rotating bits and the rest of the car. The horn did work last week, and we have the state safety check on Thursday.


dominic clancy

I had a similar problem with my brother's MGB. It lost continuity part way down the (collapsable) column.

I ended up running some solder into the joint between the middle and lower parts of the column and continuity was restored.

Have you tried earthing the rack to see if that has any effect?
Dave O'Neill 2

Sounds like just a bad ground... clean the contact up and should be ready to blow

Also check the bullet connectors

Prop




Prop and the Blackhole Midget

The entire wiring loom is new.

There is continuity between the copper ring and the steering shaft, but not from the shaft to the rack or body. The rack is earthed, and if I bridge the shaft to the rack, the horns work.

So how / why is the shaft isolated?
dominic clancy

Had the same problem - cured by running a separate earth from the outer column to earth at the rack end. I don't understand how the column/shaft aren't earthed either but it works and the midget horns belie the size of the car!
Jeremy Tickle

I was going to say I've just cured exactly the same problem but lookingt at your second post i guess it's different. I have continuity between the rack and column but not from the rack to earth - probably because of the thickness of the paint. I have run an earth wire from the steering rack grease nipple to one of the rack mounting bolts on the body.

have you tried cleaning up the splines on the rack and the clamp on the column to get a beter electrical contact? perhaps run some solder into the splines to tighten up the fit?
graeme jackson

Archive:- "earthing the steering column".
Nick and Cherry Scoop

Thanks for the comments. We have solved it for the time being by turning the engine earth strap ( which is somewhat longer than standard, so it may have been a battery earth strap in an earlier life) a complete turn around the colum so it acts as a coiled sleeve. That is not going to wear out in a hurry. Next time we are in that area to replace the clutch fork, we will make a small earthing strap as defined in the archive.

Safety test on Thursday afternoon, so fingers crossed!
dominic clancy

Had to earth my rack to the rack mounting bolts to make the horn work when I rebuilt the Frog. Most peculiar.

Rob
Rob aka MG Moneypit

This thread was discussed between 11/08/2014 and 14/08/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.