Headlights - Dip beam issue

[Rob P]

Having searched unsuccessfully over the weekend I thought I would ask if anyone can confirm my suspicions around an issue that started on Saturday.
After a nice run out to the Local Lotus Club meeting, driving home I had the need to engage the lights due to the failing light.
Upon switching on the side lights all was fine, panel lights switched on and again all OK, pulled the switch to raise the headlamps and pods raised OK and came up with lights on full beam.
Switched the rocker to engage headlights and no headlights at all, side lights and panel lights still work OK, moved stalk on the steering to main beam and blue light on in the speedo but no headlights.
If I switch the rocker switch for the lights into the middle position for the side lights only then main beam comes on but no little blue light in the speedo.

Is this likely to be just a failure within the switch itself? didn't want to start stripping down the dash unless people think this could be the root cause.
I would welcome any feedback
Thanks

[William2]

Sounds like the switch has failed internally. It could be the relay but I'd put my money on the switch.

[RichardS]

I would check the dipped beam relay first. I have had similar symotoms in the past due to a failed relay.
Richard

[Rob P]

Cheers Guys, I'll have a look at the relay first as I'm assuming that is easier to get at then trying to get the switch out.
I'll need to do some reading as this is the first real work I will have had to do on the electrics on this car since purchasing. Is the relay easily accessible?The switch I assume is dashboard unbolted to get it out?

[pharriso]

Is the relay easily accessible?

Should be left (correction!) hand inner fender, just ahead of the radiator.

[Gray]

Headlamp relays are normally on left (nearside) inner wing on RHD cars.
Check earths and if fitted the microswitches on the headlamps - I've had them fail leaving no headlights in the distant past. One microswitch should inhibit the headlamps when they are down and the other initiate the headlamp flasher if fitted, I've never had one that has worked. I normally delete the microswitches, although there is a risk from headlamps heating the fiberglass if left on in the down position.
Earthing problems, relays and microswitches are the most likely cause in my experience due to their exposed location, but headlamp and dipswitch switch possible.
I would check all earths first, good practice for future reliability, then see if there is voltage to the relays from the headlamp switch and dipswitch. If voltage then then microswitches, then the relays. If no voltage check the dipswitch first as its easier.

Gray

[Rob P]

Cheers to all for the feedback, multi-meter will get an airing in the next day or so.
Appreciate the feedback

[fatboyoz]

Rob,
I have the wiring diagram in front of me.
The blue high beam light illuminates as a function of the dip switch position. It is not dependent on high beam actually being on. The power for this is from the rocker switch being placed in the headlamps ON position. If the blue lamp lights with the dip switch in the high beam position, it would indicate that there is power from the rocker switch in the ON position.
The fact that your high beam came on ( should come on flashing) when the pods were raised with the rocker switch in the side light position (or OFF position) indicates that there is power to the headlamp flasher relay, but that the headlamp flasher unit (round flasher unit with two pins) has either been removed or is faulty. It also indicates that the micro switch on the L/H pod is OK.
The headlamp system has two relays, one for dip beam and one for high beam. They have a common power supply, a blue wire that comes from the control box, L/H side of the engine bay above the footwell. Could be this power supply is at fault.
The earth for these relays is also common and is supplied via the micro switch mounted on the R/H light pod. This micro switch, or the wires going to it (Black with red), could be at fault.
The micro switches do not have contacts, just an inner and outed that touch when fully extended. Could just need a clean.
Cheers,
Colin.
P.S. If you have a workshop manual, it includes the wiring diagram.

Having searched unsuccessfully over the weekend I thought I would ask if anyone can confirm my suspicions around an issue that started on Saturday.
After a nice run out to the Local Lotus Club meeting, driving home I had the need to engage the lights due to the failing light.
Upon switching on the side lights all was fine, panel lights switched on and again all OK, pulled the switch to raise the headlamps and pods raised OK and came up with lights on full beam.
Switched the rocker to engage headlights and no headlights at all, side lights and panel lights still work OK, moved stalk on the steering to main beam and blue light on in the speedo but no headlights.
If I switch the rocker switch for the lights into the middle position for the side lights only then main beam comes on but no little blue light in the speedo.

Is this likely to be just a failure within the switch itself? didn't want to start stripping down the dash unless people think this could be the root cause.
I would welcome any feedback
Thanks

[Rob P]

Thanks Colin,
Great explanation and good info for me to follow. I do have a diagram somewhere so will dig it out once work eases off to give me some spare time. Just mad busy at the moment but need to get this sorted and learn a little more about this wonderful car
Rob

[Shiny_kit]

I had a similar issue on my +2. I had replaced one of the fuse boxes, very carefully replicated the correct connections but completely failed to notice that on the old unit underneath somebody had bodged a bridge between two spades so one feed fed two fuses. New fuse box had no bridge so no output on one fuse! Won't tell you how long it took to figure that one out.