Smoking light switch. Coupe S1

[simonpen]

I know even less about electrics than mechanicals but I do know that my light switch should not start smoking when full beam is selected. The culprits seem to be the two red cables, one I think from the column, they both get very hot. I have not changed anything during the restoration so what is the most likely cause?

[jus]

Do the main beams actually light up when switched?
The wires would only really do this if they were carrying way too much current than they normally do when supplying the 60W (?) bulbs. 60W / 12V = 5A per bulb at 60W. For the wires to get that hot, they may be carrying 10x that amount. If there was a dead short (i.e. the wires went straight to ground), then they'd burn in a few seconds (but the fuse should really be blowing first), so it's worth tracing the wires to see where they go. Disconnect from the front lights and see if the wires still get warm. If they do, then there's probably an issue with the switch gear or fuse connections - which would probably have been disturbed during a renovation.

Sorry I can't help more than that.
Let us know if you find anything else worth noting when testing.
Justin.

[lancialulu]

S1 light switches can short or partially short against the chassis. The fat red wire is not fuse protected....?

[simonpen]

Thank you both. Yes the main beams do work. I have replaced the outer bulbs with H4 but they are 60w. I have bought a new switch, looking at it I cannot see how it can fail, a pretty simple thing.

[lancialulu]

Check carefully with an accurate ohm meter across the brass rivetted  parts. I noticed high resistance due to unseen corrosion under the rivet from a seemingly new looking switch. It failed to make the lights operate correctly.

[simonpen]

Problem is solved by the fitment of a new switch.