Lotus Elan

Electric window motors

PostPost by: worzel » Sun Feb 15, 2009 8:40 pm

Hi

This is definitely not related to the other posting I've put on about removing dash panels- I promise!

For some months the driver side motor has been working erratically. thinking it might have been due to the switch when I recently had the dash out I checked the outputs from the switch and these were fine.

However, the motor now appears to have given up completely. Testing it off the car produces nothing. I stripped it and a visual examination doesn't suggest anything amiss- there is no scorching/burning, the brushes are virtually unworn and the commutator is clean, nothing seized etc. The curious thing is that when I tried it on the car the upward position with the window closed produced a slight dimming of the interior light suggesting it was trying to operate, the downward position didn't affect the courtesy light at all.

Anybody out there know of any other tests I might be able to perform to diagnose what's wrong other than connecting the feeds etc?

Thanks in anticipation.

John
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PostPost by: billwill » Mon Feb 16, 2009 3:18 am

Sounds like the bearings have seized.

I's strip it down & clean thoroughly. and lubricate the bearings & grease the cogs that spin the driving prongs.
Bill Williams

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PostPost by: Frank Howard » Mon Feb 16, 2009 3:33 pm

worzel wrote:Testing it off the car produces nothing.

John,

Perhaps I can help you there. You'll notice there are 3 wires coming from the motor. One is black. When I tested mine, I connected the ground to black and hot to one of the other ones. Nothing happened. I then switched the hot to the other colored wire thinking that was the way to get the motor to run the other direction. Again, nothing.

To test the motor, forget about the black wire. Connect your hot to one of the colored wires and your ground to the other. The motor should turn. To reverse the rotation, switch the two wires. Hope this helps somewhat.
Frank Howard
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PostPost by: oldelanman » Mon Feb 16, 2009 5:47 pm

I checked the outputs from the switch and these were fine.


Did you also check the earth connection to the switch ? As per previous post the motor itself is not earthed. To lower the window the switch supplies power to one of the coloured wires to the motor and earths the other one (don't know which is which I'm afraid) These connections are reversed to raise the window.
Roger
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PostPost by: SADLOTUS » Mon Feb 16, 2009 7:46 pm

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PostPost by: MintSprint » Tue Feb 17, 2009 12:53 pm

At risk of stating the obvious, I assume you're aware that the motors are just MK1 Ford Escort wiper motors?

The MK2 Escort is slightly different, but can be easily adapted, too.

If you have problems getting your existing motor working again, throw it away (remembering to keep the mounting plate and drive plate)... you can get a replacement second-hand motor from Ford specialists or Ebay for about a tenner.
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PostPost by: worzel » Wed Feb 18, 2009 3:52 pm

Hi All

Thanks for all of the input.

Update- I've now got it working- I didn't realise that "off-the -car" testing required that one feed be fed and the other feed earthed- I was using the earth and it wasn't turning.

The problem (initially at least) turned out to be the two "prongs" in the plastic top cover that form part of the contacts. These "prongs" contact the rotating part of the motor (sorry I don't know the technical term for that part of the motor). Presumably the one for the earth is redundant when not used as a wiper motor. The plastic lug thru which these prongs protrude had broken causing the contacts to drag and presumably short out the motor.

Araldite fixed that but still have a problem. The down function is somewhat erratic- sometimes works sometimes not. Lift always works. As somebody suggested is this likely to be the earth function on the panel switch or does this suggest the actual motor is the problem/

Again- thanks

John
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PostPost by: oldelanman » Wed Feb 18, 2009 5:45 pm

Hi John,
If the motor works OK off the car I would suspect the switch itself - perhaps the contacts got fried by the short in the motor itself. As it works raising the window the supply and earth connections to your switch and the wiring from the switch to the motor must be OK.
Roger
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