Headlights and indicators glowing on

Topics relating to the Lotus Exige S1 (series 1)
Evoman
Posts: 136
Joined: Fri Apr 03, 2015 12:00 pm

Folks, I'm trying to figure out what is perhaps an earthing issue with my car.

Turn on the sidelights, works fine, turn on headlights and the indicators light up to a dim glow and the front driving lamps light up too...

Main earth strap could be a culprit? How do I access this? Is it only visible from underneath requiring undertray to be dropped?

Any top tips much appreciated 👍
Evoman
Posts: 136
Joined: Fri Apr 03, 2015 12:00 pm

So checked main earth strap, cleaned it up and refitted, no change. So I guess wiring somewhere or earth in the front bay area?
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Fonzey
Posts: 1188
Joined: Tue Nov 27, 2018 12:17 am

Does the S1 have the same switchpack setup as the S2? Mine died and it had all sorts of weird symptoms around the illuminations etc.
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deggles
Posts: 183
Joined: Tue Feb 26, 2008 12:22 pm
Location: Leeds

Could be the front earth point, it's a bit harder to get to than the rear unfortunately :( Image

Did you remove and clean under the step-washer on the rear chassis connection - mine was well and truly crusty :o - there needs to be a good connection to the bare ali where the anodizing is removed Image
This solved a few weird electrical issues I was having, the most hilarious being the engine stayed running with the key removed if I left the headlights on :lol:
Evoman
Posts: 136
Joined: Fri Apr 03, 2015 12:00 pm

Really helpful diagrams, thanks :thumbup:

Yes I cleaned up the engine bay earth point although it really wasn't too bad, perhaps has been cleaned up in the past. I also sprayed some contact cleaner in there too and cleaned up the tip of the screw thread.

I'll try the front earth point next. Looks well hidden, I guess once the battery is out it will be more visible.

I didn't see the engine management -ve binding post - is that also on the Exige? I will take a look next time I'm back at the car which will be towards the end of the week.

Cheers
winthattt
Posts: 1066
Joined: Fri Feb 12, 2010 4:45 pm
Location: Sunny Derbyshire

Are the main beams on, in which case the driving lamps should be on? Do you have a multimeter? It sounds like the power to the headlamps is making its way to the indicators with a high resistance, which is why the lamps are dim. Don’t leave them on for long as something could get hot.

If you switch the headlamps off do the indicators work normally, including flashing at the correct rate?
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deggles
Posts: 183
Joined: Tue Feb 26, 2008 12:22 pm
Location: Leeds

Evoman wrote: Mon Mar 29, 2021 6:27 pm I didn't see the engine management -ve binding post - is that also on the Exige? I will take a look next time I'm back at the car which will be towards the end of the week.
I don't think so, no, with the ECU behind the seats in the Exige I assume it just earths via the bulkhead connector and main engine loom. The service manuals are mostly Elise, with an Exige supplement as an add-on, so things often don't align. I’ve PM’d you a link to a copy along with the parts list :thumbup:
Evoman
Posts: 136
Joined: Fri Apr 03, 2015 12:00 pm

winthattt wrote: Mon Mar 29, 2021 8:15 pm Are the main beams on, in which case the driving lamps should be on? Do you have a multimeter? It sounds like the power to the headlamps is making its way to the indicators with a high resistance, which is why the lamps are dim. Don’t leave them on for long as something could get hot.

If you switch the headlamps off do the indicators work normally, including flashing at the correct rate?
Hi

Main beam off when the indicators glow and driving lamps light up... I don't have a multimeter and also have no clue how to use one! Can't be too difficult right?! :crazy:

Indicators work normally as do hazards without lights on but I think the side repeaters don't flash when the lights are on but fronts and rear indicators do. Flash rate slows a bit then too.
C8LGY
Posts: 36
Joined: Thu Jun 13, 2019 10:27 pm

A multimeter is a handy thing to have, at least to check voltage. I can recommend the Proster VC 99 (or VC97 looks the same), as its seems pretty accurate when compared to a Fluke (the gold standard but they start at £140) and is under £30 on Amazon.


In the meantime, can you narrow it down to a circuit that is the problem? Electrcial issues can cause weird symptoms, which don't always make sense, but if you can find an issue that's a good start. Couple of things for thought:

1. Do all the lights work?
2. Have you had anything replaced or broken recently?
3. Any 'suspicious' areas (water in a light, chafed wiring etc.)?

The other thing you could try is to remove the light fuses and then replace them one by one, to see if things work as expected. I would start with the following:

A22 High Beam
A20 RH dip
A21 LH dip
A17 RH driving lamp & sidelight
A16 LH driving lamp & sidelight

If you replace a fuse and it suddenly misbehaves and/or affects another circuit, pull the fuse on the other affected circuit and see what happens. Let us know how you get on!
winthattt
Posts: 1066
Joined: Fri Feb 12, 2010 4:45 pm
Location: Sunny Derbyshire

I have had a quick look at some wiring diagrams and think the poor earth suggestion is a good option. I think you have cleaned the earth connection for the headlamps? It must be that one. Even if you have done that try adding a nice chunky wire to the earth post and then connect the other end to earth (battery).

What “could” be happening is: a poor earth will mean the battery voltage 13v drops across the headlamps and the earth, say 10v and 3v. As the indicators connect to the same earth post the 3v earth will now drive the indicators which also earth at the back of the car. 3v becomes 1.5v across each indicator, so they glow dimly.

That’s my wild guess!
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