The Lotus Grand Tourers

Hi I had window motor (Delco ) failures a few years back and bought a couple of adapted Bosch Motorst from Pete at PNM Engineering.
Having fitted these the windows worked great. UNTIL... The drivers door motor just stopped working completely - or rather didn't work via the switch. Connect a battery directly to it and it works fine.
I am now Just finishing a lot of major jobs of the old dear, an 89 SE which has been up the ramp for three years. The last mechanical job, which I have left till last is sorting out the Drivers door window.

As the carrier had failed I have fitted anew drivers door window and including the framee from Lotusbits - no problem there. All fitted OK.

SO.. The window switch on the drivers side door operates the Passenger window on its own LH side of the switch. Substitute and plug the drivers door plug into the switch and the LH window works fine. Sorry for that unwieldy explanation. Swithching over both the RH and LH sides of the drivers door window switch operate the Passenger door window - perfectly. But the Drivers door window remains inoperative on either side of this switch.

Where does one start testing for a circuitry- fuse - relay failure? It appears there is no power getting to the plug on the Loom in the drivers door. Five connections in the drivers door window switch alone and all sorts of other stuff hanging around?

The Fuses are all good, if you have suffered a similar Lotus problem? Any helpful ideas on what or where the fault may be and how to test for it will be most gratefully received.
Thanks

If I'm reading this right - all the switches are OK (i.e. they can operate the passenger window). The window motor is OK as it will work if power is applied directly to it.

In that case - is there power to the switch? and if there is, does that power get as far as the motor? and is there a good earth to the motor (it's easy to forget it as it's a flying lead that connects to one of the motor mounting bolts)? You either have a problem before the switch or a problem between switch and motor.

There are no relays involved in the windows, just fuses and switches - and the driver's side is the easier one as there's only the loom to that door to worry about. BUT - because that door gets used more, the loom is more likely to break.

I think I'd start by swapping fuses 30 and 31 to see if the problem moves to the other door, and then progress from there. There are really only 4 wires to worry about - YG which provides power to the switch and then SN and SR which carry power to the motor. And finally the earths.

Thanks for the very prompt and helpful reply.
Your understanding of the problem is perfect.
BTW. It was never intermittent, it just stopped suddenly suggesting a component failure, Hopefully not in the wiring loom.

I will check your suggestions out and reply to you. Its the tracing which I am a bit stumped on but will follow your lead here.
Thanks again and fingers crossed.
Mike

Check all the connectors, too. They do corrode internally and that causes significant voltage drops across them.

My passenger door window lift recently stopped working. I found 12 volts on the disconnected loom. I took the motor out, not difficult, and on the bench it worked fine on a separate battery.
I noticed that the motor has no distance limit switches and my conclusion is that the motor simply stops as the window reaches full up or down travel, and does not burn out as it is designed to just stop.
The window glass had some tight spots for movement in the cloth vertical runners.
I removed the window frame, there are two small black screws you may not know are there, remove them to allow frame removal. My frame is not badly rusted but I am told (Angus) that frame rusting can distort the vertical cloth runners.
I obtained some new runner material from Woolies Trim (Item 317 Universal Window Channel at 2.50 PSterl/ml) and the profile is the same as the removed runner and I cleaned the rust from the window frame. I am now fitting it all back.
You may find that a weak power in the loom cannot allow the motor to overcome a glass in a tight frame.
Let us know.

Dave the cog.

Thanks to you two guys for your helpful comments.
We can now see that there is no power to the drivers side window at the switch Y/G
Only problem I have is how to identify the fuses. There is no 'helpful' location diagram on the box of fuses under the scuttle to the right of the steering wheel.

Has anyone an image of the fusebox layout with descriptions so I can identify the Fuses 30 and 31 as kindly suggested by A Marshall.
Haven't got an owners manual and the parts manual doesn't describe the fusebox.

Help!

Have a look in this thread http://www.lotusexcel.net/phpbb/viewtop ... =7&t=10165

Thanks Angus that is great