Dodgy headlights

[Rozzer]

I have to admit to a significant failing in owning old cars - my auto-electrics is limited to knowing when the battery is flat.
So when the headlights failed to work on my S1.5 when I came out of the pub the other night, but the sidelights, indicators, horn and so on all worked still, I was (and continue to be) a bit mistified.
I have had a look at the wiring diagramme (might as well have not bothered) and can't see a relay - is there one? If so, where is it mounted? Could both the headlight bulbs have blown simultaneously? Might the switch be faulty - does this happen? Silly question, as the Prince of Darkness is involved, but someone might have had the same issue.....

Any thoughts ladies and gents?

[StressCraxx]

I have to admit to a significant failing in owning old cars - my auto-electrics is limited to knowing when the battery is flat.
So when the headlights failed to work on my S1.5 when I came out of the pub the other night, but the sidelights, indicators, horn and so on all worked still, I was (and continue to be) a bit mistified.
I have had a look at the wiring diagramme (might as well have not bothered) and can't see a relay - is there one? If so, where is it mounted? Could both the headlight bulbs have blown simultaneously? Might the switch be faulty - does this happen? Silly question, as the Prince of Darkness is involved, but someone might have had the same issue.....

Any thoughts ladies and gents?

Hello Rozzer,

There is a headlamp relay under the dash, behind the speedo and tach, attached to the firewall.

[mazlot]

Ashton,

there is a motion switch attached to the body, adjacent to each of the headlight pods. These play up.

The relay is down there too, on the passenger side.

[richardcox_lotus]

Yes happened to me - check the motion switch (aka microswitch ) they work like the courtesy light switches in the inside front of the door pillars, and should plunge in and out. They can get grubby and stick.

Regards
Richard

[Rozzer]

Thanks gents - plenty of options to try there - when I get the Elan back down off the hoist

[lotusS2guy]

It's all part of the headlight flashing circuitry. If you don't care about this, simply bypass the relay behind the dash. My headlights stopped working with fewer than 1,000 miles on my new 1965 Elan. Under warranty, the dealer's mechanic gave me the option of replacing the burned relay (he said it would happen again) or by passing it. I opted for the latter and never had another problem.

Apparently the spring that actuates the headlight-flasher microswitch at the headlight pod resonates and causes the microswitch to chatter which causes the contacts of the main relay to burn due to inductive arcing. It's surprising that Colin put in all this extra junk which does not add lightness (it seems to add darkness!!)
Herb
26/4618

[billwill]

If you have 4 fuses on the LH side in the engine compartment, one or more of those is for the headlights; check the fuses first.


B

[RotoFlexible]

If you have 4 fuses on the LH side in the engine compartment, one or more of those is for the headlights; check the fuses first.

B

In an S1/S2 that hasn't been modified, the headlights are not fused. The headlight switch is fed directly from the control box (regulator), and the switch feeds the headlights through the headlight relay (controlled by one microswitch that detects the headlights are raised) and the dip switch. A failure in the "flashing" circuit (either the other microswitch or the flashing relay) cannot disable normal headlight operation; the flashing circuit provides power to the main (high) beams independent of the normal headlight circuit.

The main headlight relay is buried at the front top center of the space under the crash pad. They pretty much built the car around it. Its only function is to make sure you don't leave the lights on when you lower them. It can be bypassed, but then you have to remember to turn off the lights.

The two fuses in the little fuse box near the control box (the other two fuses are spares) - one of them protects the horn circuit, and the other one protects almost everything else in the car.