Lotus Elan

Wiring circuit for relays in the window motor layout

PostPost by: ericbushby » Mon Apr 15, 2013 4:09 pm

Hi john and everyone else,
Whilst on my hobby horse, when buying tags try to get the fully shrouded ones and thereby reduce the chances of accidental short circuits when poking about with screwdrivers etc. near electrical connections.
I`m done. I`m going now.
Eric in Burnley,
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PostPost by: billwill » Mon Apr 15, 2013 6:08 pm

A good idea..... son... :D

I think the usual auto relay's pins are designed for the blue connectors.
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PostPost by: stugilmour » Mon Apr 15, 2013 6:22 pm

Adding a quick point regarding fuse size. We had a bit of a discussion on this a while back. OK to try a 5 amp fuse for your motor supply wires, but you may find it is a bit light in practice.

Granted the Plus 2 motors are different (more below), but I am guessing you may have a similar issue as I had. I ended up using 15 amp fuses for each motor (supplied separately in my non-stock setup). The motor would run fine with a 5 or 7.5 amp fuse, but they would blow when the motor reaches stall at the full up or full down position. One had to be very quick at releasing the switch! :) Problem solved with 15 amp fuses. For sure start with a smaller fuse size, but may have to up-size if you have a similar issue.

Key point is to make both the supply wires as large as practical to reduce any voltage drop to the motor. I used this size thin wall cable from Vehicle Wiring Products, which is available in many colour choices:

Ref 25. 28/0.30mm, 2mm2, 25amp.
?0.50 per metre. ?37.90 per 100 metre reel.
Plain colours also available in 30 metre reels @?12.79
Typical applications. Headlamps, fog & driving lamps,
rear screen heater, windscreen wiper motor.

As noted, the Elan is pretty unique in the use of re-purposed windshield wiper motors. There was a thread a while ago where a lister found IIRC readily available rebuilt Mustang wiper motors could be used, but it may have required using your existing output gear deal (sorry not familiar with Elans, see the thread). Anyway, here is the thread in case you have continuing issues with the motors. I used rebuilt Cardone motors for my Plus 2, and the quality is excellent, readily available in NA at your local Auto Parts store for reasonable cost, and they take a core on your old motor. Just get the new motor in your hands before giving them the core so you know what to retain.

body-chassis-frame-f36/power-window-lift-motors-cross-over-parts-t25540.html

Regarding the Excel window motors John mentioned in this thread...

electrical-instruments-f38/window-motors-t27878.html

I am completely guessing here, but I expect they are different from the Elan motors. Don't want to hijack the Elan wiring thread, but suffice to say the 'common' way to do window motors uses two power wires (one for up and one for down) and a ground, which is used to operate the motor. This is how the Plus 2 motors work, which are a very commonly used GM part (Chev, Buick, Olds, etc.). This was long before the GM purchase of Lotus; they just raided the Delco parts bin in this case. :) Humorous side note; they installed them backward to GM (left motor on the right side of the car & visa versa) just to make installation a PITA. :)

Plus one on moving your wires so a diode equipped relay will work. From your photo your relays don't have a diode, but better to wire to the standard.

HTH & doesn't confuse things. I think you have got it now. :)
Stu
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PostPost by: ericbushby » Mon Apr 15, 2013 7:11 pm

billwill wrote:A good idea..... son... :D

I think the usual auto relay's pins are designed for the blue connectors.


Hello Bill.
No, that isn`t how it works. The colour code is for the wire size only. The other end can be anything; such as different size rings, flat tags or several sizes of slide on tags.
For instance you can get a red, blue or yellow tag to fit on a 3/8 bolt.
Hope this is clearer.
Please believe me using the correct fitting is just as important in this as it is in any other job.

I just found my petrol pump to be fixed with one imperial screw and one 13mm. !!! They are close but not good enough.
Eric in Burnley
1967 S3SE DHC ( should really be putting the petrol tank back in. The suns out here)
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PostPost by: billwill » Mon Apr 15, 2013 11:15 pm

Oops, yes, Eric is right, I'm wrong about the meaning of the colours on the crimp connectors.

Going by the CPC catalog (http://www.cpc.co.uk) Red and Blue female spade connectors are readily available to fit either 4.8 mm or 6.3mm spades, Yellows only listed as 6.3 mm.

I think the usual auto relays have 4.8mm spades, so if you used the usual yellow crimp connectors there, then they are a bit large for this job and it would be better to use the fully insulated ones which shroud the actual connector. So I reccommend blue 4.8 mm crimp connectors.
http://cpc.farnell.com/pro-power/stfdfd ... tt=cn11425

Image
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PostPost by: archigator » Tue Apr 16, 2013 12:45 am

Eric, several of these connections have two wires into one connector. The wire is 14GA. You are correct in that blue connectors are for 14-16GA wire, but the yellow connector is for 10-12GA wire, which allows for the two 14GA wires to attach into one connector. And yes, fully insulated would be best, but this is what I had on hand. These relays are going to be located in the cab; all of my connectors in the engine compartment are fully insulated. :D

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PostPost by: ericbushby » Tue Apr 16, 2013 11:14 am

Gary
Yes I understand that.
you just have to know what is correct and then do your best.
Regards,
Eric in burnley
1967 S3SE DHC (nearly ready for testing)
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PostPost by: worzel » Wed Apr 17, 2013 8:31 am

Hi- again

Just a short follow up to my original posting.

Firstly, my apologies- the circuit I attached does work (I should have re-checked my work) so my thanks to whoever first devised it (although in my defence I didn't say it was wrong just that mine didn't work).

Now I'm only reporting this so no brickbats please. What started this rewire was the gradual decline of the operation of the driver window. I'd overhauled the motors about 18 months ago and for the first 12 months or so since they worked fine. Over time however the down function started to become erratic, sometimes working sometimes not. I found if I operated up that usually down function was restored. Eventually even this trick didn't work and even up stopped working.

Checking things I found that there was feed from the dash switch to both functions. Thinking it unlikely that both connections had come adrift inside the door I checked them anyway, found them fine and just on the offchance connected the earth wire from the motor to an earth point. Immediately both functions worked.

Now I know some will say (correctly) that these motors don't use an earth so what's going on?. Maybe my car is an odd one but I'm pretty certain the wiring is std (I'm the second owner since 1978 and I know for a fact the first owner wasn't the hands on type). I notice also that the 72 print works manual I have does show an earth for each motor.

I had this problem with another car- a 89 Excel I had some time ago. When I first bought the car the driver window wouldn't work. Stripping the motor revealed the commutator was pretty dirty. Cleaned up function was restored. However, after a few months the motor stopped working. Another clean and it worked. This was repeated for about 3 years until in the end I bought a good secondhand motor. The same problem however kept recurring. It was only when I changed the metal door beam that I found inside the door, hidden in the corner an unattached earth wire that was meant to link the motor to the door beam.

Problem solved, I had no more trouble with this for the next 8 years when I sold the car. Incidentally, the Excel motors work in a similar fashion to elan ones ie they will work without the earth attached but clearly that have some function.

Just my observations- I'm not drawing any conclusions from this experience- but will definitely leave a working earth attached.

Regards

John
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PostPost by: billwill » Wed Apr 17, 2013 11:39 am

That earthing situation is certainly peculiar. There's a faint possibility that the internal wiring of your motor is shorted to its metalwork. You can check this with an ohmmeter.

I went down to my Elan to check the colours of the wires yesterday and noticed that on the door which I checked (right hand) there are 3 wires going into the tube at the door hinge and the black one has been cut off short inside the cabin, so my windows are working fine with no earth wire at all.

The beautiful redrawn wiring diagram by Peter L Wisley of the Elan S4 wiring harness, which is a file on this site somewhere,uses the relay circuit as first described by Colin (with pin 85 as positive), so perhaps that is where he got it from. Evidently it is a well-known circuit for such a function.
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PostPost by: oldelanman » Wed Apr 17, 2013 12:33 pm

I don't understand how earthing the case could possibly make the motor work in both directions - the polarity needs to be reversed to achieve that.
Roger
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PostPost by: billwill » Wed Apr 17, 2013 1:12 pm

oldelanman wrote:I don't understand how earthing the case could possibly make the motor work in both directions - the polarity needs to be reversed to achieve that.



Me too, best hypothesis, assuming it is a standard motor, is that the wiring on the rotor has a break in the loop, but the end or ends of the wire are shorting to the metal of the rotors. With the circuit completed by current flowing through the metal bearings, from one brush or the other; i think this might give half the torque of a proper working motor,

But honestly this is so unlikely that I doubt my own theory.
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PostPost by: ricarbo » Wed Apr 17, 2013 1:19 pm

If you're worried about the connectors not being fully insulated, why not add some heatshrink? Less trouble than starting again.
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Richard
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PostPost by: worzel » Wed Apr 17, 2013 2:45 pm

Hi

Re comment by "Oldelanman". My apology for not clarifying this point about the motot springing into life with an earth attached. What I should have said was that the motor began to operate properly using the dashboard switch in both directions and with the earth attached. Removing the earth stopped the motor working. just to repeat- my works manual does show the motor earthed via the courtesy light earth.

Regards

John
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PostPost by: AussieJohn » Wed Apr 17, 2013 5:00 pm

Is it possible that there is a capacitor internally in the motor to stop arcing on the com.. which requires an earth?
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PostPost by: billwill » Wed Apr 17, 2013 5:14 pm

worzel wrote:Hi

Re comment by "Oldelanman". My apology for not clarifying this point about the motot springing into life with an earth attached. What I should have said was that the motor began to operate properly using the dashboard switch in both directions and with the earth attached. Removing the earth stopped the motor working. just to repeat- my works manual does show the motor earthed via the courtesy light earth.

Regards

John


Interestingly perhaps, you would get those symptoms if your car ALREADY has the two-relay circuit hidden somewhere inside the door structure. The output circuit of the relays requires an Earth connection.
Bill Williams

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