Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Faulty dip beam

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Problem: my car is a Roadster S1 3l 2004. The dip beam is not working, as well as the horn. The lights were a bit on-off at first, before they disappeared totally. Everything else is working, exept the horn, that gave in only when I changed the switch stalk - with no effect to the lights. When I supply current directly from the battery to the fuse sockets I get light. So the bulbs are ok, and they must be well grounded. The two fuses are intact, both by visual inspection and measuring ohm. The switch stalk was changed under the suspicion that it was the problem, but in vain. Being brand new it should be ok, and the multicontact connecting to it looks good. The horn was working untill I changed the switch, then mysteriously went silent when I reassembled. The horn shares fuse with the radio, which is working fine, so it can't be the fuse either. I am suspecting a faulty relay, but according to the wiring diagram (and to a number of gurus...) there is no relay. I cannot hear any relay click when I switch to the intact main beam, but might it be an electronical relay in spilte of the diagram not showing it? Or there is a fault somewhere between the new and presumed intact switch and fuse panel? Any good ideas? anyone having a wiring diagram specific to this model? All help will be appreciated.

Only have wiring diagram for 3.7 Roadster but that has no relays for horn or headlights. The common denominator seems to be stalk switch you changed and/or wiring/connectors from steering wheel, not relays or fuses.

Robbie, if you look up under the front wings there are quite large bunches of bullet connectors - I would try those as they are very exposed to corrosion and carry the circuits you mention

What Jon said abive. Some of the bullet connectors around the wing stays need checking. I lost a light on the offside a while ago and that was why.

The horns earth at the steering wheel boss, so check the spade connector is still connected.

The S1 Roadster has two horns.check the live feed to each, and test the earth return. They are under the front panel.

The fuse is very marginal for twin horns, and I upgraded mine to....... from memory 15A.

It's possible you have a hairline crack in the fuse, which will allow the radio to work, but overheat with horns, so try changing it.

Yes, will check connectors, but bear in mind that BOTH the lamps went off at the same time. So the fault has to be somewhere proximal to a left-right ramification. And the fact that I get light when I supply current from the battery to the fuse socket, should indicate that the all the circuitry distal to the (intact) fuses are patent. So that leaves the suspect area somewhere between the (new and hopefully intact) switch and the fuse panel, including the panel itself. And the horn remains a mystery....

Again referring to 3.7 Roadster diagram the horn and headlight controls share the same dash connector C109. Would not be surprised if earlier Roadster is not similar - very likely the area where you have the problem. Good luck finding it

Richard, any possibility sending me the diagram? Or a link where I can find it? I do have a diagram saying "Roadster" but not which model. Got it from GoMog or Morganatica, cannot remember which. Might be the same as you have, or it might not. Anyway, worth a try. You will all be updated when it gets resolved...

Not sure that would help Robbie as info gleaned from looking at several 3.7 Roadster diagrams. I have looked at the GoMog wiring diagram you referred to though and it is different. Unfortunately it also lacks the detailed diagrams for individual aspects of Roadster electrics shown in the 2014 on parts manual. Nevertheless I think you should be looking at the 9 pin connector behind dash from steering wheel area to loom.

You can download wiring diagram for earlier Roadster here.

ETA: Horn push trigger is purple/black cable, dipped beam feed blue/red cable from connector to loom. Hopefully this will help in fault finding.