Lotus Elan and Lotus Elan Plus 2 Forums

Advice please. Window motors not working from switch, so connected direct to a 12v battery at connectors next to door, Windows work fine down and up. Put meter at supply from switch and measured 11 volts at motor, car battery at 12.56v, motor no response. I did run an additional earth, still nothing.
Luckily (not)I have the dash out, p.o. Had fitted an interior light delay module that went into fault and burnt out a couple of earths and the feeds at switch. On with that at moment.
Should I increase cable size from switch to motor? Any suggestions.
.

Les.

I put relays on mine as per several suggestions and it works great now.

Bob

Unfortunately measuring voltages is not much help,you can have 12 volts at a certain point but very little current flow,you need to make sure the path has little resistance and this is what is slowing down the windows....bypassing wiring with new sections will tell you something but you really need to make sure all connections ( live and earth ) are clean and good.....Low resistance.

John

If the voltages you quote are at the motor then you are getting a small voltage drop in the normal supply and fitting a relay as previously suggested would help. This may however mask a poor connection somewhere in the supply line (although I would expect some votage drop)
Another thought which may be the main cause could be that the window is giving too much resistance to allow the motor to start at the lower voltage and reduced resulting power. I had one window that was very reluctant to move when the engine wasn't running and charging the battery but I sprayed the side channels with silicon lubrication spray and it has worked fine since then(2 to 3 years ago).

Ed

As you already have the dash out I would be fitting relays and a new feed wire for the load, it always seemed to me that there was far too much voltage drop due to weight saving (thin) cable? On mine I ran a fused feed from the starter solenoid terminal, split to each side of the dash near the door hinges where I fitted the relays. I also ran new heavier earth leads to the tunnel ground points, you can then use the existing switches and wiring to control the relays without putting load on them. I ran new heavier cables through the doors to the motors, stripped and cleaned the motors and fitted very good brushes to the drivers motor from a spare passenger side motor, all works like a modern car now, well, you know what I mean!

I've taken the rocker switches apart and cleaned the contacts inside and that makes them work so much better and the window's travel so much faster.

Roger

vxah wrote:As you already have the dash out I would be fitting relays and a new feed wire for the load, it always seemed to me that there was far too much voltage drop due to weight saving (thin) cable? On mine I ran a fused feed from the starter solenoid terminal, split to each side of the dash near the door hinges where I fitted the relays. I also ran new heavier earth leads to the tunnel ground points, you can then use the existing switches and wiring to control the relays without putting load on them. I ran new heavier cables through the doors to the motors, stripped and cleaned the motors and fitted very good brushes to the drivers motor from a spare passenger side motor, all works like a modern car now, well, you know what I mean!

Caution: If you do use relays which is a great idea if done as above, carefully consider before putting the hot wires in the doors, subject to chafing as the door is opened and closed. The approach above doesn't do that, but it's an important safety concern even though the doors aren't conductive themselves. Fusing is also important but not foolproof.

Thanks to everybody. Looks like I will fit four relays as per drawing in photo gallery. Will be cleaning all terminals, replacing the burnt out wiring and refitting dash. Well that's the plan.

Ta Les.

Brian Buckland has an article on window motor cleaning & repair. in the current Club Lotus magazine.

Elan45 wrote:I've taken the rocker switches apart and cleaned the contacts inside and that makes them work so much better and the window's travel so much faster.

Roger

I carefully took apart my toggle switches and cleaned them and, as above, the circuits work fine now.

You don't need relays, they just add complexity and difficulty in future troubleshooting

The switches are not a particular failure point

All the wiring to the windows could use a larger gauge

Odds are if you blew a ground behind the dash, it also is the windows.
IIRC they are grounded at the base of the dash, so they probably wont work with the dash un bolted