Lotus Elan

Window problems

PostPost by: prezoom » Sat Mar 24, 2018 3:58 am

After being the fastest of the two (2) windows, My drivers (LHD) door window decided today to start only going about half way up. It just stops, and no amount of trying lift or wiggle the window will allow it to go any further. Pulled the door card and checked for any thing that seemed to be causing it to bind, but everything seems normal, it just stops. I sort of wondered if there was some sort of limit switch that may have come loose or somehow moved. My workshop manual does not seem to have much in the way of trouble shooting, and it is not the correct one for a 130. Pictures do not match what I am finding. Electrical issues are basically pretty simple on these cars, battery (B+) looking for ground/earth (B-). About the only complex circuitry is contained in the DB10 relay. if anybody has had an experience like this, and can help point me in the right direction, it would be greatly appreciated.
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PostPost by: nmauduit » Sat Mar 24, 2018 9:45 am

I don't think there is a switch on mine, I can see the interior light dimming when the windows are reaching the top : that may be a quick and dirty way to diagnose, checking if the amount of current increases when the window stops (works better with a weak battery...)
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PostPost by: Bud English » Sat Mar 24, 2018 2:10 pm

Rob- I don't think your car has a second DB10 relay used in the window circuit. The DB10 relay is in the tail light/brake light/hazard circuit.

The wiring diagram in my manual, dated '74, Has a diagram for the +2S 130 and shows only the two dash switches and the motors in the circuit. I can scan what I have and email it to you if it will help.
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PostPost by: JonB » Mon Mar 26, 2018 9:53 am

I second Bud's diagnosis.

Plus 2 S130 has two relays that I can see: The starter and the horn. Window motors, headlights, rear window demister, heater motor and wipers are all wired direct to their respective switches. To add insult to injury, there are only four fuses in the whole car.

My plan is to rectify this, but I may need as many as 14 relays to do it.
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PostPost by: ericbushby » Mon Mar 26, 2018 10:21 am

I cannot see a reason to fit relays in the window motor circuits.
As I said on the other window topic recently, mine take 3 Amps up and 1.5 Amps down. with a maximum current of 5 Amps when stalled.
As this is only for ten seconds at a time, nothing is going to get warm. The switches are capable of handling far more current than that.
If you have a problem with slow windows, you should fix the problem and not add complications.
IMHO.
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PostPost by: JonB » Mon Mar 26, 2018 1:39 pm

Right, then. How about a diagnostic checklist for slow windows? Any suggestions?
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PostPost by: ericbushby » Mon Mar 26, 2018 2:22 pm

With nearly all fault finding it is usual to pick a test point to split the job into two. Before that point or after.
First put a 12 volt supply directly to the motor to eliminate electrical supply problems.
If it then runs sweetly it is weak electrical supply.
Next find another test point to split the wiring into two parts. maybe at the switch would be OK.
This is sometimes known as the `black box method`. Gradually make your `box` smaller by dividing the faulty area into two parts until you have the fault surrounded.
What is in each box doesn`t concern us at this point if it works OK
The idea is that you do not need to know how something works in order to know that it is working. Hence the `Black Box`.
Only when you have located where the fault is, do you need to learn how that bit should work.
If on the first test the window is still slow, then it is probably either a faulty motor or friction overloading the motor.
Again try to disconnect something to test before or after this point.
I have not worked on that area myself so cannot advise in detail here.
The point I want to make is this method applies to many situations that seem to be a mystery at first not only electrical faults.
Cheers
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PostPost by: prezoom » Mon Mar 26, 2018 3:05 pm

After taking a day off and resting my frazzled brain, I am thinking it probably is a mechanical problem. The electric motor moves the window within a small range, at its normal (?) speed. Taking a deep breath, it looks like an upward and outward day. At least, Saturday, even with the recalcitrant window, was shear joy, with a 170 mile drive through he local mountains. Made better by courteous motorists pulling over to allow me to pass. Getting together with friends for the drive even made it better.
Rob Walker
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1964 Sabra GT
1964 Elva Mk4T Coupe (awaiting restoration)
1965 Ford Falcon Ranchero, 302,AOD,9",rack and pinion,disc,etc,etc,etc
1954 Nash Healey LeMans Coupe

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PostPost by: ericbushby » Tue Mar 27, 2018 10:33 am

I now see that Rob`s question at the start refers to a Plus 2.
My current readings are taken from my Elan Series 3.
From the other windows topic I now read that the Plus 2 has a different system and the motor may draw about 12 Amps.
In this case I can accept that fitting relays may be a benefit.
Best of luck anyway,
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