Lotus Elan

Dash switch numbered connections

PostPost by: tonyabacus » Fri Aug 14, 2020 7:52 pm

Replacing the dash wiring seems the best option when trying to sort out a PO "enhancements" and this has been a constant source of questions over the years. Whilst the actual job of changing the harness is not so difficult, one of the bigger issues appears to be which wires connect to which numbers on the different switches, especially when a PO has used the same colour cables for his enhancement work !

Unfortunately the WSM only gives a clue to some on the very early cars, so those with S3 - Sprints are pretty much left to trial and error. Does anyone have either a full schedule of which wires attach to which terminals on the different switches or a comprehensive set of pictures to take away some of the trial and error method.

I found out earlier today that possibly the Gordon Lund book on Lotus Elan Restoration may possibly have a picture if someone can check if they have the book.

Those with any info if they can respond, I will attempt to put it all into a form that will make this task easier for those that perhaps find it a little difficult to follow wiring diagrams. So any contributions welcome.
Tony
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PostPost by: steve lyle » Sat Aug 15, 2020 12:43 am

For simple switches, such as the panel lights, interior lights, or windshield washer, where the switch is either on/off on a single wire, it of course doesn't make any difference which wire goes where on the switch.

For complex ones, like the the hazard switch, windshield wiper or the 2-speed fan switch for the heater, what I did when rewiring my Sprint dash was use an ohm meter to determine when the switch is "on" for specific connections, then connect the wire for that function to that contact. Same thing for the headlight micro-switch, which is a general purpose switch that has contacts that go 'on' when actuated, and contacts that go 'off'.

Maybe someone has the documentation you're looking for, but if not maybe this will help.

In any event, make sure you test the panel out before putting it back on the car!

Regards,
Steve
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PostPost by: fatboyoz » Sat Aug 15, 2020 6:30 am

Hi Tony,
This is what I used. Needed it after years of looking at the instrument panel on my desk in the study.
Credit to Gordon Lund for having the foresight to note down the connections before pulling things apart, unlike myself.
Cheers,
Colin.

7E26984E-07D2-49FC-8525-EE8E571FEAE6.jpeg and





tonyabacus wrote:Replacing the dash wiring seems the best option when trying to sort out a PO "enhancements" and this has been a constant source of questions over the years. Whilst the actual job of changing the harness is not so difficult, one of the bigger issues appears to be which wires connect to which numbers on the different switches, especially when a PO has used the same colour cables for his enhancement work !

Unfortunately the WSM only gives a clue to some on the very early cars, so those with S3 - Sprints are pretty much left to trial and error. Does anyone have either a full schedule of which wires attach to which terminals on the different switches or a comprehensive set of pictures to take away some of the trial and error method.

I found out earlier today that possibly the Gordon Lund book on Lotus Elan Restoration may possibly have a picture if someone can check if they have the book.

Those with any info if they can respond, I will attempt to put it all into a form that will make this task easier for those that perhaps find it a little difficult to follow wiring diagrams. So any contributions welcome.
Tony
'68 S4 DHC
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PostPost by: tonyabacus » Sat Aug 15, 2020 9:47 am

Steve/Colin
Thanks both for the replies.

I think you're right Colin that we often are too quick to get on with things and rely on our memory, so Gordon does deserve some credit for this. As you say Steve you can always check things out with a meter but this can be very time consuming and if you are not so good with electrics then the signals you get can be a little confusing.

So at least this diagram will provide a starting point for most people to be able to check their existing connections before pulling things apart. Any deviations will then at least act as an alarm to check into the reason why and allow for some further investigation. I suspect from a cursory look at the diagram that this will apply equally to Sprints and possibly the Fed cars as I can't imagine Mr Chapman changing wire colours much. But if anyone has different info please feed it in and I will include it later.

But in any event it is advisable to test the whole panel before installing, for as I have found there were a couple of suspect wires under the harness tape which could just might have prevented things from working as they should, if not more hazardous in causing a burn through or fire.

As I progress I will take more notes and pictures to assist others.
Tony
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PostPost by: fatboyoz » Sat Aug 15, 2020 1:25 pm

Hi Tony,
A link to routing of dash panel wiring.
viewtopic.php?f=36&t=25365

Cheers,
Colin.
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PostPost by: The Veg » Sat Aug 15, 2020 5:08 pm

When I dismantled my dashboard I used a P-Touch labeler to label each wire with a legend such as 'Fan top left,' Headlight bottom right,' etc., as well as labeling where top was on each switch since they were coming out and getting disassembled and cleaned. Of course this method assumes that the connections are correct in the first place, which they were as I eventually learned they were, partly from an electrical diagram I got from somebody which contained similar indications to the picture in Colin's post.
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PostPost by: awatkins » Sat Aug 15, 2020 7:34 pm

“ .... you can always check things out with a meter but this can be very time consumingl”

Doesn’t have to be.

Draw on a pad of paper a rectangle for each switch, and within draw a dash for eaxh terminal (vertical or horizontal as the case may be) as viewed from the rear.

For each switch position (up, center (if any), down): choose a color pen or pencil: Red, green, blue, for example.

Put the swirch in each switch position, and for each position, go around the terminals putting the meter across each possible pair of terminals. For a basic two position there is likely just one pair. For a basic three postion there are likely three: top pair, bottom pair, and top to bottom). Four terminals, 6 pairs; 5 terminals, 10 pairs; 6 terminals, 15 pairs.

Every time the meter says you have contact, draw a line between that pair of terminals, in the corresponding color.

Be patient and attentive when there are more than three terminals.

One minute per switch times <=10 switches = 10 minutes max.

For the ignition switch make a table 4x4: columns are switch positions (accesory, off, on, start). Rows are terminal numbers 1-4. For each switch position, check each possible pair of terminals (there are 12), put an x for each that the meter says are connected. 15 sec. per pair x 12 = 3 minutes.
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PostPost by: pharriso » Sat Aug 15, 2020 10:46 pm

I use my iPhone to photograph any/everything before I take it apart, electrical or mechanical. Useful reference. When “ assembly is the opposite...” :roll:
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PostPost by: tonyabacus » Wed Aug 19, 2020 9:16 pm

Thanks again guys.
Not come across the grid pattern of checking out a switch (awatkins) so will try that and see what we get.

I did start to take photos Phil, but the basic problem was that the PO had chopped back wires into the harness and modified so many connections but using a single colour cable which made trying to identify which wires did what a real headache, to add to it some of the switches had been put back upside down and cable reversed on terminals, hence the shout out for a diagram with the terminal numbers and the correct colour cable that should be connected.

I have now ordered a new loom which will resolve part of the refurb, just got to connect up to the correct terminals, so again if anyone has some clear photos of the rear of the dash and switches showing colour it will be much appreciated.
Tony
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PostPost by: pharriso » Wed Aug 19, 2020 10:49 pm

tonyabacus wrote:if anyone has some clear photos of the rear of the dash and switches showing colour it will be much appreciated.
Tony


Tony, sorry if mentioned already, LHD or RHD? What year car?

I have photos of UK RHD S4 & LHD Sprint that I used when I repaired my harness, pm with your e-mail address if you would like either.
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PostPost by: Bigbaldybloke » Tue Aug 25, 2020 10:13 pm

Whatever you do take loads of photos, photo the complete rear of the dash to show the harness position, and take detailed pictures of each switch from more than one direction!
I replaced my dash and did a few mods like changing the ammeter to a voltmeter and adding an electric windscreen washer pump etc and the pictures were regularly used to confirm which wire went to which terminal.
Change is inevitable, except from a vending machine!
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PostPost by: tonyabacus » Wed Aug 26, 2020 9:08 am

Do you have copies of the photos you could send me as thats what I have been looking for
Tony
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