Hi All,

The window on the passenger side of my 1985 W123 wasn't working, so I took the door panel off and put 12v (10amp) directly on the regulator using my battery charger to check if there was a problem with the power supply.

The problem is that when I put the power on, the regulator works for half a second and then stops. When i switch the power off and on again, the same thing happens.

Does anybody know why this happens?

Thanks!

Try it with a battery. I use a 18V battery from my power drill.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thank you so much! Ill give that a try.

Also, where do i solder exactly the new wires. on the regulator, there are two pins for both the positive and the negative pin. Do i solder it onto the top/larger pun, or the lower, smaller pin?

Thanks again!

Connect the 12V to the motor. There are only two wires which I know of. Why would you solder anything to them? You are just checking it for operation.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Hi Mike, thanks for your reply.

I need to solder new wires on the motor because the wires snapped real close to the motor, so i couldnt just connect the wire soldered to the motor to a new wire using a wirenut. So using a solder, I heated the tin and took the old wire off, but now I can't remember where the wire exactly connected... (i know, rookie mistake...)

Thanks for you help again!

Unfortunately I don't know which wire is which, however once you get that figured out, it sounds like you might be drawing too much current due to load on the motor. There's a thermal/current draw overload switch inside the motor housing that might be getting too hot and breaking continuity. On my '85 w123, I have refurbished 3/4 window regulators by removing them, cleaning all the nasty grease off the gears and linkage, and re-greasing them. I also had quite a bit of flex in my regulators, so I ended up flattening them out by clamping them to a 2x12 and flexing the aluminum until it was back to a reasonably flat shape. You might also grease the window rails. I used a combination of silicone spray for the slides and thicker silicone grease for the mechanism.
A simple test to see if the overload switch might be causing the problem is to thump the motor while applying voltage. This rattles the switch and seems to have a fairly decent chance of fixing the problem short-term. You can even just slam the door while holding the switch, if you don't want to remove the door panels.

thank you so much for this. Ill definitely will give this a try next weekend!