Problem with headlight wiring

[robb4100]

just finished fitting a new front harness and all seems to work except the front headlights. the parking lights go on when the switch is pushed up one position but the headlights do not come on when the switch is pushed to the second position.

The elan is an S2. AM I correct that there are only 4 places where the wiring could have been fouled up.

1) the three-way toggle switch on the dash
2) a switch/relay (?) under the dash
3) the relay near the front of the car
4) a second switch near the front relay

I took pictures of the dash area before I broke down the old wiring and the new wiring is hooked up the same way at the toggle switch as the old (headlights did work before the new harness was installed). (in order blue/red;red;blue/black; blue)

My picture of the 4-plug switch under the dash is not clear but it appears to show the wires clockwise (blue/yellow; blue/brown; blue; green) and that is the way that it is wired. the cap with the electronics came out of the case as I was worked on it.

Can someone please send the correct order for attaching to the relay in the front. Mine seems to have 4 poles but only three are being used. I wired this bit a couple months ago and did it as I removed the old harness so I think I have it right. I can send a picture if that will help.

Bottom line is I must have something wrong and am looking for a good way to check it out. Also I suppose a switch or relay could be bad so I would like to rule that out.

Any suggestions?

thanks

Robb

[1964 S1]

Hello, where is your "relay in the front"? I'm looking in my S1 without finding it, maybe an S2 has another relay.? Without knowing what I'm talking about I'd rotate wires on your "front" relay to see if I could get the desired results.

[1964 S1]

ooh, I forgot, as is so often suggested here, did you neglect a ground wire somewhere? What do you mean by a new front harness?

[RotoFlexible]

Robb,

This is hard to diagnose remotely. You need a circuit diagram and an inexpensive multimeter (no Lotus owner should be without one). If you don't have a circuit diagram, I can scan mine and post it.

That said, I have my main headlight switch in front of me. Looking at it from the back, you should be able to see terminal numbers. The numbers run 1-8 but there are only 5 terminals, at least on my switch.

Terminal 1, upper left corner on the outer edge of the case: heavy Brown/Blue (main feed from regulator)
Terminal 4, upper right of inner back of the case: Red (parking lights). The fact that the parking lights work suggests that 1 and 4 at least are correctly wired.
Terminal 6, lower right of inner back: Blue-brown (feed to "relay flashing main bean" terminal "C2")
Terminal 7 lower left corner of outer case: Not used.
Terminal 8, lower right corner of outer case: Blue (feed to underdash relay terminal "C2")

The underdash relay, reading left to right, is:
Yellow-blue (from headlamp microswitch behind RHS headlamp)
Blue (from light switch T8)
Brown-blue (to headlamp dip switch)

The headlamp dip switch is either on the floor or on the steering column. In either case, it is pre-wired with the correct color codes. There is a brown-blue wire carrying current into it, and two wires carrying current out: blue-red to the low beams, and blue-white to the high beams.

The "relay near the front of the car" is probably on the LHS and is the main beam flashing relay, and the microswitch near it is activated when the the headlights come up. You can ignore it for purposes of getting the headlights working.

On the RHS, there is another microswitch which controls normal headlight activation. One side has a yellow-blue wire to the underdash relay (left terminal) and the other goes to ground.

So here's how power gets to your headlamps:

From the regulator to the light switch,
From the light switch to the headlamp relay (underdash),
From the headlamp relay to the dip switch,
From the dip switch to either the low- or high-beam circuit,
And through the headlamps to ground.

Those are all spots you need to check. Also, the headlamp relay will not operate unless the headlamp microswitch is operating correctly. One quick check is to short-circuit around this switch. Its only purpose is to be sure the lights are off when they are down.

Good hunting!

[robb4100]

Thank you Andrew,

I bypassed the RH microswitch blue/yellow to black and the headlamps worked fine. I tried the same on the LH side and this time the headlamps started to flash. Any suggestions as I try to chase that down?


Thanks again

Robb

[robb4100]

Hello, where is your "relay in the front"? I'm looking in my S1 without finding it, maybe an S2 has another relay.? Without knowing what I'm talking about I'd rotate wires on your "front" relay to see if I could get the desired results.

I will try to post some pics of both relays tomorrow

Robb

[RotoFlexible]

Thank you Andrew,

I bypassed the RH microswitch blue/yellow to black and the headlamps worked fine. I tried the same on the LH side and this time the headlamps started to flash. Any suggestions as I try to chase that down?

Nothing to chase! That is correct operation. When the headlights are off (switch in "off" or "parking light" position) and you raise the pods, the "overtaking" lights flash. I think this is illegal in the US but my car came fitted with it. The microswitch failed and was removed long since. (Here, I think using this might get you shot; not so in the more civilized parts of the world.)

You can safely short-circuit the switch on the RHS but you have to remember to turn off your headlights when you retract them. I did this for many years, but recently I bought a brake light switch that resembles the original microswitch and fitted it with success. (Auto Electric Supplies p/n 081401, www.autoelectricsupplies.co.uk) The force needed to actuate it is a bit more than the original, so you may need to fit a stouter spring to the headlight return spring.

[robb4100]

Outstanding!!!

Thanks folks, once again you have bailed me out.

Robb