Not starting, could the horn issue be contributing to this?

[AlBundy]

The van is currently at the body shop for some rust repair and bodywork fixes, but after having left it there, they haven't been able to get it going.

I will post more info later when I have it, but I would like to know if issues in the steering wheel electrics, I.e the horn not working at all in normal circumstances, but occasionally going off when turning right could be part of the same issue. The steering itself isn't smooth, there is some friction so it needs some tlc anyway.

The van is a 1986 LHD 1.6 diesel.

Any suggestions for what to look for before I go to the garage and try sort it out would be very helpful.

[Stesaw]

The horn issue is probably to do with the horn ring on the underside of the steering wheel. When you put pressure on the wheel as you turn it, it can ground on the column causing the horn to go off. Make sure the ring is in one piece and not damaged, then go from there (remove the steering wheel to check) mark the splines up first with tipex or something, otherwise you'll have a wonky wheel.

I doubt it will cause any problems for it starting/not starting.
The starting could be a number of things, not getting it going is pretty vauge . Could be a low battery, might be to do with glowplugs... might even be that you're out of fuel

[AlBundy]

Is definitely not fuel, or battery, the glowplug light comes on when I half turn the key and goes off again, so assuming they are OK. It was a bit temperamental before but now not going at all.

It doesn't turn over when full turn of the key, so possibly the immobiliser not switching off, or a fuse gone. I am told there may be a switch to disable the immobiliser so may try test that if it can be found.

[lefty67]

How long ago was it last started?
Fuel might have drained from pump so might need priming.
Also make sure all the earth's are nice and clean particularly the statermotor one.
Check glow plug fuse (long metal strip) in black box in engine compartment.

[AlBundy]

Latest update. A wily expert bypassed the immobiliser using magic (or expertise), and the engine started fine. They has suggested that its either the wire linking the ignition to the starter motor that has deteriorated, or an issue with the ignition itself.