Electrical confusion...

[Robbie693]

... not uncommon with me!

I have a problem tith the interior lights on my S/130. They work and come on with the passenger side door via the plunger switch but not on the drivers side. I thought it was just the offside plunger switch but this seems ok as it extinguishes the lights when they are on, just doesn't turn them on when I open the door.

Also the panel lights switch doesn't turn on the interior lights either (although it works for the instrument lights).

As far as I can tell all the wiring is as the wiring diagram, although it's difficult to tell when it disappears into the loom.

There are unbroken connections from the panel switch to the door switch (purple and white wires to each side) and I can get the panel switch to work the interior lights if I move the power wire (red) from one side of the switch to the other (spare) terminal, but then the instrument lights don't work...

I know it's difficult to diagnose remotely but can someone explain to me how it should be wired, incase I am reading the diagram wrong?

Pic of diagram:

[rgh0]

The contacts in the door switches can become dirty so that the spring pressure is not sufficient to close the contact and turn on the lights when the door is closed. Clean the switches and see what happens

regards
Rohan

[Emma-Knight]

The two seater electrics works this way (original from the workshop diagram and my car) :

Instrument electric plus red/white via reostat switch to red main to light switch. Should not be connected to door switch / panel light switch.

Courtesy lamp panel / map light have power from permanent plus via ignition switch main brown / blue power supply (double connector on switch) and purple line from there to purple panel light through bulb and down purple black to purple white to panel switch. Here crimped together
with purple white from the doors - when opened connected to mass via black lines on doors. When panel switch is operated, connected to mass via black line from switch to mass point in dash loom.
Connection to permanet plus is needed so light turns on when doors are opened - You wouldn't want to wait for the door lights till ignition key is turned ...

This would be when black (earth) is minus (negative ground) but no difference in wiring when positive ground. Just twixed polarity

(just looked at the picture - though a bit rough, I can see the purple main runns via fuse box - do You have a better resolution picture (jpg maybe)?

Anna

[Frank Howard]

Robbie,

First of all, as far as the door switch is concerned, I agree with Rohan. The door switches are one of the cheapest parts on the car and they are prone to corrosion however they don't have to be replaced. Clean them up and then put some dielectric grease on them.

Also the panel lights switch doesn't turn on the interior lights either (although it works for the instrument lights).

I don't believe the panel light switch is supposed to turn on the interior lights, rather I believe the panel light switch is supposed to turn on the instrument lights only. At least that is the way it is on a +0.

The way to think about the interior lights is as follows:

There is 12V going to the interior lights all the time, even when the car is turned off. It comes in through the brown wire to the courtesy (rear quarter) lights and it comes in through the red/white wire to the map light on the dash. The reason these lights don't stay on all the time is because although they all have purple/white wires connected to each other which serve as the ground wires for the lights, normally the purple/white wires are not grounded. However, once the purple/white wires are grounded, the lights do come on. Because the purple/white wires are all connected to each other, there are three ways for the purple/white wires to be connected to ground. They can be connected through either door switch when the door is opened, or they can be connected through the "Interior" switch which grounds them when it is switched on. Hope this helps.

[ppnelan]

The Panel Lights switch in a (late?) +2S/130 has two positions. The first switches on the Panel Lights and the second should switch on the interior lights.

I would check the earth connections - if it's like an Elan, they will have 'ring' connectors to an insecure screw on the door switch, then a black wire going off to a proper earth point somewhere behind the dashboard. If anything electrical stops working, it's always a good start to check the earths

The Panel Light switch itself might be at fault - good luck in accessing this without removing the dashboard though...

Matthew

[Robbie693]

Hmmm. Well it seems the +0 has quite a different wiring arangement, but I think I understand how it works a little better now - thanks to all.

I did check the door switch and cleaned it up. As it actually cuts the lights off when the door is closed, does this mean that it must be operating correctly?

It seems that the power to the lights goes from the fuse box (purple) up to the passenger side light, then out the other side (purple/white) down to the door switch, somewhere along the way meeting with the other purple/white wire coming from the back of the panel swich. The drivers side light is powered from the wires on the passenger side which loop across the roof.

The back of the panel light switch has four terminals, one seems to be spare, which looks like this diagram (viewed from the back):



Red wire comes from lamp switch via thermal cutout (power?), red and white go to the instrument lights and purple/white go to door switches...

Maybe Matthew is correct that the switch is at fault, because if I move the red wire to the spare terminal the switch operates the interior lights rather than the instrument lights...?

PS. Sorry Anna, I don't have a better scan of the diagram - I lifted that one from another post. Anyone else have a scan?

[Emma-Knight]

Thoughts: does the switch have two or three positions?
(two on off funtions would be used separately - might the interior PW
line be connected to wrong switch?) The use of map light should be independent from instrument light, which are operated through main light day drive and normal light contact.

Anna

[Robbie693]

The switch is a 3 pos - off-on-on, I have tried moving the connections around but can't get both functions to work - only one or the other.

The map light is completely independant - it is the swing out-on type below the glovebox

[Elanintheforest]

The spade on the switch that you have no wire going to should have an earth (black) wire which also connects to the defrost switch. There are a bunch of them around there, hooking up the cigar lighter as well into a common earth. I guess it's just come off and is now invisable in the rats nest that is Lotus wiring
Mark

[Robbie693]

Really? Is that on a Plus 2?

I did wonder but the diagram shows that spade as unused so I chickened out - my knowledge isn't good enough to make me feel confident that I wasn't going to do any damage

[Elanintheforest]

Have confidence, mon brave! I have a couple of dashboards in front of me right now, from which I've been drawing a physical schematic. when you get into it, they are different to the workshop manual! The schematic is drawn from 3 different dashboards, so errors excepted...it's right. I can send you a copy if you can't get enough resolution from the photo...either as a bitmap or the original Powerpoint.

The three dashboards I've been using are all from the last version of the 130...with the dashboard mounted fuse box (where the ashtray used to be). I'm sure that the others will vary in some way.
Mark

[Robbie693]

Nice one Mark - you are a star

That diagram is really useful - saved for future reference!

There definately is no earth wire hanging around so I'll have to tap in to the connector from the defrost and cigar lighter earth.

Thanks very much

Robbie

[Robbie693]

Well I tried the earth wire addition but still no joy, does this mean the switch is broken?

Any other ideas pleeeease?

Thanks in advance

Robbie

[elansprint71]

I may be stating the obvious here, but the reason for the panel light off switch was to decrease battery drain when you parked at night with the side-marker lights on. Remember that when these cars were new, the UK law required lights at night on all roads, not just those of over 30MPH as it is now.

Sincerely,
Michael Caine.

[john.p.clegg]

Micheal
And here was me thinking that it was to help visability after dark...

John