Lotus Elan

Lights are doing weird things & I?m baffled

PostPost by: marklowe » Thu Oct 29, 2015 4:45 pm

My Elan S4 was rewired earlier this year by the company that repainted it, everything has been working fine even the headlight flasher, but yesterday was the only time that that lights and windscreen washers have been tested over a prolonged period.

Yesterday I used the car to work and back a total of about 35 miles with the lights on and wipers and wash used occasionally , everything was working fine when I set off, but on retuning I noticed that the headlights had stopped working, on doing a full check I found.

Nether the headlights or main beam work, but the headlight relay buzzes.
Side lights work on there own, but if you indicate in ether direction both indicators and side lights flash.
If the headlight flasher circuit is activated the indicators and side lights flash instead of the headlights.
Windscreen washer has stopped working.

I have individually tried:
Changing the headlight relay.
Disconnecting the headlight flasher.
Checking the engine bay wiring loom connections back as far as the connections to the dash loom.
Engine bay wiring loom for visible signs of burning.

Non of this has left me any the wiser, any suggestions of where to look next gratefully received.

Thanks
Mark
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PostPost by: nmauduit » Thu Oct 29, 2015 5:13 pm

poor connections (including at the fuse box) may cause surprising behavior, like letting through enough current to switch a relay but not enough to power the headlamps that are behind : you may check for that using a voltmeter (for headlamp with and without bulbs connected to vary the load). Oxidized plugs (increased contact resistance) or wires (copper section reduced) may cause that sort of symptoms, so with the added flasher issue, you may want to check the grounding, too (my guess is humidity is increasing these days, unfortunately).

good luck !
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PostPost by: stevebroad » Thu Oct 29, 2015 5:44 pm

My experience has been thet most electrical problems such as those you are experiencing on the Elan are due to bad earthing. With more than one circuit affected and one circuit affecting another points to this even more strongly.

The fact that it has been rewired also points to an earth issue, IMO.
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PostPost by: PeterK » Thu Oct 29, 2015 6:18 pm

I also would look to an earth issue.
A classic symptom is side lights flashing with indicators, but the cause could be either at the front or the rear. However, given the headlight issue, I would start looking at the front - especially corrosion under the earthing nut & bolt.
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PostPost by: mbell » Thu Oct 29, 2015 7:40 pm

Like the other guy's I'd be looking at the earth at the front of the car.

The indicators will earth through the side lights if the earth connection is bad. So it is a big sign your problem might be with the earth connection for the lights. A bad earth would also disable the headlights.
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PostPost by: Elanconvert » Thu Oct 29, 2015 7:57 pm

sounds like it rained for at least part of your trip?
I would suspect water ingress either causing a short or affecting earthing.......

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PostPost by: marklowe » Thu Oct 29, 2015 9:16 pm

Thanks for the replies.

I?ll have a look at the earth tomorrow, it makes sense as it is common to all the effected lights and probably to the washer pump that also isn?t working, the rear indicators seem to work normally and they have a separate earth.

Thanks
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PostPost by: marklowe » Fri Oct 30, 2015 9:27 pm

Today I removed the paint from the radiator support bracket where it meets the body bobbin, normal service has been resumed by the lights. The car was previously wired with a ?special? wiring loom using different earthing points so this hadn?t previously been an issue.

Thanks to all that pointed me in the right direction
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