Lotus Elan

Dashboard test, electrical problems

PostPost by: The Veg » Sun Aug 05, 2018 12:07 am

After WAY too much time apart and working on details (or being delayed by life), I've got the dashboard sitting in the car temporarily to test things.

The bullet connections have all been replaced by Molex plugs, on which I spent many hours with the diagrams making sure that the circuits would all connect correctly.

So I connected the battery after making sure it had somewhere north of 12V in it, turned the key, and...nothing.

After some poking around I realised that with the ammeter replaced by a voltmeter, I needed to restore the connection from the solenoid to the hot fuse. With that done, I get these results:

-Hot fuse is always hot.
-Switched fuse is hot when ignition switch is on.
-Ignition light comes on.
-Starter will turn (but does not engage- mechanical issue?).
-Headlights seem to work but the wiring colours don't completely agree with either of my diagrams and were not properly labeled at disassembly so correct connections at microswitches need to be worked out.
-Nothing else functions.

Other than the connections at the microswitch, do the more experienced among us see any other potential bugaboos I should check, based on what does and does not function?
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PostPost by: 1owner69Elan » Sun Aug 05, 2018 1:54 am

Grounds?

The replacement wiring harnesses do not contain all the necessary ground wires. For example, on the regular Elan there is an independent black ground wire looped between instruments. Won’t come with a harness. Easy to create, but I used my original one as it was in good shape.
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PostPost by: lotusfan » Sun Aug 05, 2018 10:57 am

I agree with the comment about grounds but there is a very important thing to do before you do anything else.

Install a fuse in one of the lines from the battery, maybe around 20 Amp, to prevent your loom going up in smoke.

You then need to proceed in some logical sequence, getting each piece right before moving on. Good starting point is to switch on sidelights, then headlights, then panel lights etc.

Good luck and keep us informed.
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PostPost by: The Veg » Sun Aug 05, 2018 2:16 pm

1owner69Elan wrote:Grounds?

The replacement wiring harnesses do not contain all the necessary ground wires. For example, on the regular Elan there is an independent black ground wire looped between instruments. Won’t come with a harness. Easy to create, but I used my original one as it was in good shape.


I'm still using the original harness, and the big multi-ground lug that goes on the bobbin-bolts is connected by a jumper-cable to the battery, since the 'board is loose so I can get behind it.
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PostPost by: The Veg » Sun Aug 05, 2018 2:28 pm

lotusfan wrote:I agree with the comment about grounds but there is a very important thing to do before you do anything else.

Install a fuse in one of the lines from the battery, maybe around 20 Amp, to prevent your loom going up in smoke.

You then need to proceed in some logical sequence, getting each piece right before moving on. Good starting point is to switch on sidelights, then headlights, then panel lights etc.

Good luck and keep us informed.


Thanks. The systematic approach is what troubles me, because maybe it's just me, but between the two aforementioned wiring diagrams the stuff in the dashboard doesn't seem so much like a group of discreet systems as much as like one big organic blob of weird interconnections. I guess that's where I was hoping someone could offer some helpful insight. I'll keep plugging away at it, and maybe something will start to make some sense.
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PostPost by: billwill » Sun Aug 05, 2018 3:26 pm

The wiring diagrams that are laid out like the wiring loom are confusing and almost no help at all in understanding the electrics.

A diagram like the following which shows the typical logical connections of the instruments is much more helpful to understanding how it all works, even if it does not exactly comply with the requirements of your particular car:

Image
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PostPost by: pcarew » Sun Aug 05, 2018 11:36 pm

I've just finished installing a new dash in my S3 (literally this weekend). Like you, I also decided to add Molex connectors. 4 x 15 circuit connectors.

My car is a RHD S3, ***but***, it has a mostly S2 wiring harness. I believe that the factory did this alot, probably to use up stock.

Anyway, I created a spread sheet that identified every connection on my dash. I've attached it to this posting.
Hope it helps.
FaciaWiring.xls
Dash/Facia wiring spreadsheet
(49 KiB) Downloaded 53 times


I also labeled each connection to the connector.
20180721_134258.jpg and
Back side of new dashboard.

20180804_171417.jpg and
End Result.
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PostPost by: The Veg » Mon Aug 06, 2018 1:23 am

Thanks guys, I think I mostly just needed to vent a bit about it- thanks for indulging me. We Yanks mostly don't do the 'stiff upper lip' thing all that well.

Anyway, I didn't have time today to get it totally sorted, but I think I'm hot on the trail of a bad connection. Keep fingers crossed!
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PostPost by: The Veg » Mon Aug 06, 2018 1:28 am

pcarew wrote:Like you, I also decided to add Molex connectors. 4 x 15 circuit connectors.


*4?*

Your dashboard looks to have about half as many switches as mine and I fit it all into two 15s. That said, if I were to do this job again, I'd probably break it up into one 15 and some smaller connectors.
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PostPost by: pcarew » Mon Aug 06, 2018 2:17 am

The spreadsheet I uploaded to the thread, details all of the connections.

I pretty much replicated all of the dash connections through the molex connectors.
IE I didn't consolidate / piggy back any of the grounds. They each got their individual connector pin. Same for the supply wires
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PostPost by: pcarew » Mon Aug 06, 2018 2:57 am

For understanding the wiring, I found the colour code desciption useful: http://www.dimebank.com/LucasColours.html
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PostPost by: The Veg » Tue Aug 07, 2018 2:05 am

Progress!

So I've found one bad connection. The green wire from the switched fuse to the dashboard was mis-connected.

Before finding this, yesterday I got the wires on the microswitches sorted, so the headlamps (both beams) now work correctly. Interestingly, the ignition light no longer comes on but that's a low priority and I'll come back to it later.

With the green wire sorted, the turn signals (and their indicator in the big clock) work now, as do the hazard flashers- but only when either turn signal is engaged. I know these cars are quirky, but is that correct? As the signal lever is on the wrong side of the column, such a quirk wouldn't surprise me. :mrgreen:

The window motors aren't connected but the voltage appears in the wires when commanded.

The Rear Screen switch makes the corresponding lamp come on, but that's all it does. I'm assuming that that switch controls a rear defroster, which this car doesn't have.

That's all that works for now, but it's definitely progress.
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PostPost by: gjz30075 » Tue Aug 07, 2018 8:42 am

Ben, the hazards should work by themselves, and with the key off. That's the point of the hazards. That's the
way my Sprint works.
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PostPost by: The Veg » Tue Aug 07, 2018 1:06 pm

That's what I figured. Oh dear.

This is where I get into trouble. One wiring diagram shows what colour wires come out of which places along the looms but not the actual runs, and is fairly close to what my car has as it's the diagram for a federal car a few months before mine was made. I have a book that has several diagrams that show actual runs, but none is for the right variation of federal car and they have some differences.

So I'll keep at it and see if between these diagrams I can divine what's supposed to be going on. I've got a few hours to play with it today but then I"ll be away for a week or so, so if you don't see any updates for bit, fear not- I haven't given up.
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PostPost by: The Veg » Tue Aug 07, 2018 9:49 pm

One more update before I go on holiday: one success and one more question.

Success: got the hazard lights sorted. First thing I did was check all connections in both the hazard and turn signal circuits, and everything looked right. I made sure that power was in all the right places. Check. I checked each flasher-unit independently. Each one worked properly in the turn signal circuit but the hazard circuit continued to be dead unless a turn signal was on, and this malfunction only needed a flasher-unit to be connected to the turn signal circuit. I was agonising over the perplexity of it when I reviewed the diagram and something about the hazard switch didn't seem right. A quick check revealed that the blue wire was on the wrong terminal, the one at the bottom instead of the one in the middle. AHA! Now the hazard circuit functions as it should!

Now for today's question: the HEADLAMPS rocker switch has three positions. From reading about its functions in the owners manual, I gather that it should stay in any position selected, yes? But it does not- it defaults to center and will return to center if pressed in either direction, just like one of the window switches (which work properly, so it's not one of those in the wrong hole). Just for clarity, there are two other three-position rockers, PANEL/INT and FAN. Each of these two will stay in any position selected, which seems correct. The switches aren't mixed-up, are they?
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