Help! Electric Window Problem!
Discussion
Passanger side window on the 400se not working since purchase. Drivers side works. Took the passenger door apart, motor and mechanism working fine direct from battery. Problem is between switch and motor. At the motor connector there is power on the switch down motion only, but window does not move up or down unless powered direct from car battery. I am thinking of buying a new switch (if I can find one) but before I do that are there any suggestions from our car electric experts on this forum. Any help, advice or tests I can try would be greatly appreciated.
Tony. TCB.
Tony. TCB.
Flood the switch with WD40 or a proprietary switch cleaner and operate it several times to clean the contacts.
Check all the wiring loom connections between the switch (and any relays involved) and the window lift motor.
For future well-being plop a dollop of Vaseline inside any switch, relay socket or loom connector you find along the way.
then do the same for all switches, relays and loom connectors on the whole car -
but only if you believe in preventative maintenance or you DONT believe in IIABDFI.
Check all the wiring loom connections between the switch (and any relays involved) and the window lift motor.
For future well-being plop a dollop of Vaseline inside any switch, relay socket or loom connector you find along the way.
then do the same for all switches, relays and loom connectors on the whole car -
but only if you believe in preventative maintenance or you DONT believe in IIABDFI.
ElvisWedgely said:
Does anyone have the wiring diagram for the electric windows showing fuses, relays etc. ?
Tony. TCB.
No relays involved, fuses could be anywhere on the fuse board, wiring is direct from switches to doors, usually a connector in the door but otherwise straightforward.Tony. TCB.
WD40 isn't a switch cleaner, you need Servisol.
Lucas lever switches can be dismantled and all contact faces cleaned with fine file, wife's emery board, fibreglass pencil, wet'n'dry etc.
Thanks for you replies and suggestions gentlemen. I will try to clean the switch and see if it works. It's a bit odd that there is some power coming through to the motor but no motor movement. I know the motor is OK because I've tested it. I noticed that the switch has black wires going to it, which I assume are earth wires. I wonder if these could be at fault and not earthing properly. The way I understand it, the switch supplies power and earth to the motor in one direction and then is reversed in the other direction. Where do the earth wires from the switch end up. Obviously it would be at an earth point, but were about on the car? does anyone know?
Tony. TCB.
Tony. TCB.
ElvisWedgely said:
Thanks for you replies and suggestions gentlemen. I will try to clean the switch and see if it works. It's a bit odd that there is some power coming through to the motor but no motor movement. I know the motor is OK because I've tested it. I noticed that the switch has black wires going to it, which I assume are earth wires. I wonder if these could be at fault and not earthing properly. The way I understand it, the switch supplies power and earth to the motor in one direction and then is reversed in the other direction. Where do the earth wires from the switch end up. Obviously it would be at an earth point, but were about on the car? does anyone know?
Tony. TCB.
How have you established that power is 'coming through to the motor'? If it involves a multimeter then that would tend to confirm a high resistance somewhere: without getting too technical the meter can read 12v even if there's only very little current available to it, but the motor needs to see 12v at a quite a lot of current for it to do anything.Tony. TCB.
From memory, TVR in their massively infinite wisdom thought it would be a good idea to use the bonnet release cable to carry the earth current for the cabin electrics, so you could start by finding the ends of it and making sure that any earthing straps or cables attached to it are (electrically) clean and secure. ISTR the bonnet catch has an earth strap to the chassis or engine, that needs to be 100% as well.
Wedg1e said:
How have you established that power is 'coming through to the motor'? If it involves a multimeter then that would tend to confirm a high resistance somewhere: without getting too technical the meter can read 12v even if there's only very little current available to it, but the motor needs to see 12v at a quite a lot of current for it to do anything.
From memory, TVR in their massively infinite wisdom thought it would be a good idea to use the bonnet release cable to carry the earth current for the cabin electrics, so you could start by finding the ends of it and making sure that any earthing straps or cables attached to it are (electrically) clean and secure. ISTR the bonnet catch has an earth strap to the chassis or engine, that needs to be 100% as well.
For the earth I use the negative of the battery by passing a huge jump lead in to the car for testing, so I know that's sound. There is power coming only to one of the leads of the motor from the switch and that is only on the down motion, but still no motion from the window motor. Weird, because I would have expected a down motion. Still, today I will do more tests now I know there are no relays involved. It makes matters so much easier. I'll post my findings.From memory, TVR in their massively infinite wisdom thought it would be a good idea to use the bonnet release cable to carry the earth current for the cabin electrics, so you could start by finding the ends of it and making sure that any earthing straps or cables attached to it are (electrically) clean and secure. ISTR the bonnet catch has an earth strap to the chassis or engine, that needs to be 100% as well.
Tony. TCB.
>> power coming only to one of the leads of the motor from the switch and that is only on the down motion
I must admit I haven't looked at the wiring diagram but I would expect the switch to be double pole, double throw. In the centre position it's isolated and provices a "cross over" function so supplying the motor with one polarity for down, and crossing that over for up.
It only takes one contact in the switch for the up position to be not working, and you'll get no action. Either the supply or the return ground through the switch.
In the case of the harard warning switch that stops working from time to time I just flick it up and down 10-20 times which cleans up the contacts inside, I would try this to start with. Play with it while you're driving along (the switch that is...)
These switches are quite easy to open up and clean the contacts with some fine glasspaper - hold them together and pull the paper through gets you a nice parallel contact face.
I must admit I haven't looked at the wiring diagram but I would expect the switch to be double pole, double throw. In the centre position it's isolated and provices a "cross over" function so supplying the motor with one polarity for down, and crossing that over for up.
It only takes one contact in the switch for the up position to be not working, and you'll get no action. Either the supply or the return ground through the switch.
In the case of the harard warning switch that stops working from time to time I just flick it up and down 10-20 times which cleans up the contacts inside, I would try this to start with. Play with it while you're driving along (the switch that is...)
These switches are quite easy to open up and clean the contacts with some fine glasspaper - hold them together and pull the paper through gets you a nice parallel contact face.
adam quantrill said:
>> power coming only to one of the leads of the motor from the switch and that is only on the down motion
I must admit I haven't looked at the wiring diagram but I would expect the switch to be double pole, double throw. In the centre position it's isolated and provices a "cross over" function so supplying the motor with one polarity for down, and crossing that over for up.
It only takes one contact in the switch for the up position to be not working, and you'll get no action. Either the supply or the return ground through the switch.
In the case of the harard warning switch that stops working from time to time I just flick it up and down 10-20 times which cleans up the contacts inside, I would try this to start with. Play with it while you're driving along (the switch that is...)
These switches are quite easy to open up and clean the contacts with some fine glasspaper - hold them together and pull the paper through gets you a nice parallel contact face.
Today I have opened up the switch and thoroughly cleaned all the contacts, so it's not the switch. The window motor and mechanism works fine direct from battery.I must admit I haven't looked at the wiring diagram but I would expect the switch to be double pole, double throw. In the centre position it's isolated and provices a "cross over" function so supplying the motor with one polarity for down, and crossing that over for up.
It only takes one contact in the switch for the up position to be not working, and you'll get no action. Either the supply or the return ground through the switch.
In the case of the harard warning switch that stops working from time to time I just flick it up and down 10-20 times which cleans up the contacts inside, I would try this to start with. Play with it while you're driving along (the switch that is...)
These switches are quite easy to open up and clean the contacts with some fine glasspaper - hold them together and pull the paper through gets you a nice parallel contact face.
That just leaves the wiring. I have checked all the wiring and they all seem fine. We have power at the switch, the switch earth supply is fine and the wires supplying the motor also seem fine. So. There has to be a relay somewhere. The question is where. The reason why I say there has to be a relay is because occasionally I can hear a click from the fuse box, but not all the time so I can't pinpoint the click source. Also the supply wire to the motor from the switch sometimes fails on one wire and other times on the other wire. There has to be a relay somewhere. If anyone has any ideas, please, please let me know.
Tony. TCB.
I have just noticed there are two after market boxes near the fuse box marked 'alarmtex'. I believe one of these boxes are for total closure installed some time in the car's life. This must have something to do with it assuming electric windows don't have a relay. They must have cut into the window motor power supply at some point to install this, though I have searched high and low but can't see where. I may have to run two new wires from the switch to the motor in order to by pass this contraption. Wish me luck.
Tony. TCB.
Tony. TCB.
Eureka!!! Just as I suspected there must have been a total closure system cut into the window motor supply circuit. I have just this afternoon run two wires from the window switch, bypassing the manufacturers supply wire to the motor. Guess what? everything now works. When I get the chance I will solder the two wires in permanently. Problem solved. Job done. Thanks for everyone's help and suggestions. It gave me the confidence to dig further.
Tony. TCB.
Tony. TCB.
Ah, total closure... I recall doing a few of those on cars back in my alarm days. The usual box of tricks had, indeed, a relay inside, and a thermal fuse. Essentially the alarm would trigger the closure box(es) as it was arming (the alarm had a 'dead time' where it would ignore current spikes for say 30 seconds so as not to false trigger), the window would wind up until the motor stalled when hitting the frame, then the thermal fuse would trip and cut the power after a few seconds if the closure time hadn't elapsed. This got around the fact that not all windows move at the same speed (glacial on TVRS ) so a fixed time wouldn't have sufficed.Glad you sussed it, I was running out of ideas
Wedg1e said:
Glad you sussed it, I was running out of ideas
I was running out of ideas too. Then I started searching through google for some more ideas I could try, and I came across a guy with a Chimaera on PH a little while back had a similar problem and found it was due to a previously fitted 'total closure system' found in the form of a small plastic box under the passenger side foot-well. Then I remembered seeing something similar near my fuse box. That's what gave me the idea and so I bypassed the wiring from the window switch to the window motor and it worked. Thanks for all your help and ideas. It's good to know you were there when I needed you.Tony. TCB.
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