Another long power window switch question - PeachParts Mercedes-Benz Forum

muleears · #1 06-01-2011, 06:00 PM

The driver door PW switch on my '67 250S only works to put the windows up, won't put them down. Same for all 4, up but not down. Also there is a single switch to the right of the power window switches (see pic). This single switch makes a relay under the hood click when held up, but nothing happens. So I guess I have two questions: 1. where do I go with the "no down" power windows switch and 2. what is this second lone switch for? Are the two possibly related? Is it a child safety lock? Could that possibly cause the problem with the other window switches? I guess that's more than two questions but you get the idea... Thanks in advance.

I have determined that the single switch is indeed a child lock. With this switch in the down position the door switches don't work in either direction, but up the door switches work to put them up only. The master (drivers) switch works on all windows all the time but up only.

carnut · #2 06-02-2011, 05:54 PM

I would wire around the child safety switch. Disconnect the switch and jumper the wires. I believe the switch opens the ground which disallows the window down feature.

muleears · #3 06-02-2011, 06:20 PM

Quote:

Originally Posted by carnut

I would wire around the child safety switch. Disconnect the switch and jumper the wires. I believe the switch opens the ground which disallows the window down feature.

What about the relay that clicks under the hood when I press the safety switch, could that be sticking or bad? It seems to click "on" as long as there is pressure on it but it clicks again when released.

carnut · #4 06-02-2011, 07:42 PM

I think the clicking is telling us that it is working. I'd be more concerned if it didnt click.

muleears · #5 06-03-2011, 04:45 AM

This relay is mounted on a bracket along with another relay that looks just like it but has a different part number. Also on this bracket is a small box containing 4 small fuses. These fuses were somewhat corroded on the ends, and I thought I had found my problem but I cleaned them and no luck. All four had power through them when the ignition is on. On the bottom of this bracket is another larger relay that I can't see very well. I pulled the two bosch relays and cleaned the contacts, but again, no luck.

The window switch has 4 individual switches, each with two wires on the back. When the ignition is on all 8 of these ( two on each switch) have power. Does that mean all the switches are OK? Should I test the voltage at each?

muleears · #6 06-03-2011, 08:23 PM

Well, I have concluded the switch is the problem. I took it off the car and took it apart and cleaned up the inside. Several of the contacts looked quite worn. I reassembled it and reinstalled it. Now some only go down, some only up, but if I hold each switch individually and really press, I can make each window go both ways. Is there any way to rebuild the switch by replacing the contacts or refurbishing somehow? I stretched the springs a little to improve the resistance. It just looked like some of the contacts were worn so far down that when the switch is pressed they just don't make contact. Any insight is appreciated.

carnut · #7 06-03-2011, 08:49 PM

Finger nail file and electrical contact cleaner?? on the brass pivots.

muleears · #8 06-03-2011, 09:33 PM

Quote:

Originally Posted by carnut

Finger nail file and electrical contact cleaner?? on the brass pivots.

I have them nice and clean (used contact cleaner) they just seem worn down too much, they are too short.

D&W · #9 06-04-2011, 04:33 AM

when you were orignally holding them down did you hear a clicking noise in the respective door you were trying to lower? or nothing at all?

muleears · #10 06-04-2011, 06:12 AM

Quote:

Originally Posted by D&W

when you were orignally holding them down did you hear a clicking noise in the respective door you were trying to lower? or nothing at all?

They either worked or I heard nothing at all. None of them just clicked. It appears from taking them apart that in order for the switch to work, when the button is pushed "up" for instance, there are two contacts that must touch the their corresponding two contacts in order for the window to go "up". I think what is happening is the first contact touches and stops movement of the switch any farther, the other contact is worn down so the circuit is not completed and the window wont move. If excessive pressure is applied, the switch will work.