Power to the windows

[grouch]

I've got some power windows that don't work. The fellow I bought the car from said they were working but have quit. As soon as I tear into the console, I'm going to start tracking down the power problem. If anybody has any suggestions, feel free to let me know.

The car is a 1982 Mercedes 380SL. So far I've checked the fuses. They are good and no power is getting to them. I plan to pull the window switches and see if power is getting to them. The lights don't dim when hitting them so it's not getting power to stuck motors. I don't have a schematic for the wiring yet. I don't know the routing for power. I assume it's from the ignition switch through the window switches and then through the fuse to the window motors. However, I've seen it all sorts of ways over the years.

[D_E_Davis]

I assume it's from the ignition switch through the window switches and then through the fuse to the window motors. However, I've seen it all sorts of ways over the years.

That's the most common. The window switch is the most usual culprit, along with the lockout switch.

[misterdecibel]

Are all the fuses intact?

[grouch]

That's the most common. The window switch is the most usual culprit, along with the lockout switch.

I'm trying to find where the power from the switch gets to the window switches. I've got a manual on order and it ought to be here in a day or so. It's supposed to warm up and I don't want to remove the hardtop just yet. The soft top needs replaced.

Are all the fuses intact?

Yep. They look good and test out okay. No power to them though.

[grouch]

As an update, I finally got a chance to pull the console apart to check the switches. No power to the fuses or switches. I did find one fuse about to fail and replaced it but it was for the headlight and driving light on the right side. Until I can get a schematic for this car, I'm stuck right now. :-[

[ChevyMan]

I've got some power windows that don't work. The fellow I bought the car from said they were working but have quit. As soon as I tear into the console, I'm going to start tracking down the power problem. If anybody has any suggestions, feel free to let me know.

The car is a 1982 Mercedes 380SL. So far I've checked the fuses. They are good and no power is getting to them. I plan to pull the window switches and see if power is getting to them. The lights don't dim when hitting them so it's not getting power to stuck motors. I don't have a schematic for the wiring yet. I don't know the routing for power. I assume it's from the ignition switch through the window switches and then through the fuse to the window motors. However, I've seen it all sorts of ways over the years.

You all are missing the most obvious reason the power window do not work. I've had the same problem with the passenger side window. I checked all the wirings and switches (individual AND master switch---on the driver's side window==.Nothing worked so took it to the shop. They found out the motor itself was the culprit. Works fine now.

[chiph]

If there's no power to the fuses, the only thing to do is continue upstream until you find it again.

I would look under the hood for a secondary fusebox.

Chip H.

[DonTom]

"You all are missing the most obvious reason the power window do not work."

Even a good motor will need the voltage to run it. He said there's no voltage at the fuse with ignition on.

Is there any other electrical stuff in the car that doesn't work? Other stuff that requires the ignition to be on, but does not work?

If the problem is no voltage at the fuse, remove the fuse, and then put battery plus on one side of that fuse and connect the other side to the window side of the window fuse SOCKET. Keep key out, see if windows now work. A few feet of wire will be necessary to do this test. Fuse in series with wire between battery and fuse socket.

Perhaps is an ignition switch problem, if the vehicle is too old to have a BCM (Body Control Module).

-Don-

[misterdecibel]

That's the most common. The window switch is the most usual culprit, along with the lockout switch.

I'm trying to find where the power from the switch gets to the window switches. I've got a manual on order and it ought to be here in a day or so. It's supposed to warm up and I don't want to remove the hardtop just yet. The soft top needs replaced.

Are all the fuses intact?

Yep. They look good and test out okay. No power to them though.

If there's no power to the fuses, then you need to be looking upstream of there, tearing up the console won't help.

[ChevyMan]

From non-use (not bothering to lowering and raising a window periodically), my right window tends to stick and not move at all unless I move it up and down once in a while, which greatly irks me!! (ahhh ..me!)

[grouch]

"You all are missing the most obvious reason the power window do not work."

Even a good motor will need the voltage to run it. He said there's no voltage at the fuse with ignition on.

Is there any other electrical stuff in the car that doesn't work? Other stuff that requires the ignition to be on, but does not work?

If the problem is no voltage at the fuse, remove the fuse, and then put battery plus on one side of that fuse and connect the other side to the window side of the window fuse SOCKET. Keep key out, see if windows now work. A few feet of wire will be necessary to do this test. Fuse in series with wire between battery and fuse socket.

Perhaps is an ignition switch problem, if the vehicle is too old to have a BCM (Body Control Module).

-Don-


My book came in but the color coded schematics were reprinted in black and white and are so small as to be useless. I did jumper from a hot terminal to the right power window fuse. It and the drivers side window both worked fine then. This tells me that I powered up the circuit and now I have to find out why there isn't any power to it. While unbelievably easy to work on, the puppy is quite compact on it's internal design. Basically, no poking around. You have to know where to look. The only other thing not working on the car is the dome lights. they only work in certain positions on the ignition switch and I'm not sure I tried them properly. New bulbs in them already. I talked to the dealer and they are at a loss also. It may be to early of a design but one lead is to look for a secondary fused relay on the firewall. I'm going to clean the car today and once the body is cleaned of several years of detretus, I'll be back on this. This is a car I've wnated for 30 years and I'm GOING to enjoy it.

[chiph]

Like I said earlier -- look for a secondary fusebox under the hood. It's very common on Mercedes, and increasingly common on modern cars.

Chip H.

[grouch]

Like I said earlier -- look for a secondary fusebox under the hood. It's very common on Mercedes, and increasingly common on modern cars.

Chip H.

There's no secondary box but there is a junction relay that looks like it needs a good cleaning. Grey connections and all. I've gotten Jaguars and MGs with electrical systems made by the "Prince of Darkness" going by cleaning the connections and coating them with dielectric grease. This is one big puppy. It's on the main line from the battery in the trunk to everything else. Two other items that don't work are the dome lights (new bulbs in them) and the windshield washer. The wipers work fine. I'll see how cleaning the connections work. It got rather warm today. I've still got the hardtop on since the rag top really is a rag. I was cleaning and found part of one of the back windows in the side pocket. I expect when I put it up the first time, there will be BIG holes in it. :-[

[DonTom]

" This tells me that I powered up the circuit and now I have to find out why there isn't any power to it. "

If there's nothing on that circuit that draws current, I would wire in the 12 VDC as a permanent fix so you can control the windows even with the key out. I prefer the windows to work even with the key out, I often find it to be very convenient.

But that is if there are no kids or doggies to accidentally choke themselves on the windows when you're not in the car! One of my doggies, Trixie, put her paw right on the up switch and the window came up and almost lynched the poor doggy!

I don't think your dome light is a related problem because dome lights work without a key.

Can you hear the relay click when you turn the ignition on? If so, I would be that's your problem. IOW, rely has power, but contacts need cleaning. A fairly common problem when relays are used to run motors.

-Don-

[grouch]

If there's nothing on that circuit that draws current, I would wire in the 12 VDC as a permanent fix so you can control the windows even with the key out. I prefer the windows to work even with the key out, I often find it to be very convenient.

But that is if there are no kids or doggies to accidentally choke themselves on the windows when you're not in the car! One of my doggies, Trixie, put her paw right on the up switch and the window came up and almost lynched the poor doggy!

I don't think your dome light is a related problem because dome lights work without a key.

Can you hear the relay click when you turn the ignition on? If so, I would be that's your problem. IOW, rely has power, but contacts need cleaning. A fairly common problem when relays are used to run motors.

-Don-[/color][/size]

I prefer the windows to work when the key is on for security reasons. I remember when I was a cop, we couldn't firgure out how one car was stolen without breaking the glass. The locks wouldn't open with a coat hangar but the window switch was wired direct and they pushed it down. Sliding hammer to pop the lock and a screw driver and off they went.

The dome lights only work in position 1 or 2 on the ignition switch. This car is quite different from anything I've owned before (I've had somehwere between 100 and 200 cars in my life, so far.) and I'm going slow to avoid causing more damage than I fix. I found the stumble in the engine already. The distributor cap has two latches. One wasn't engaged. I'm pretty asure when I find the problem it'll be something simple. Possibly the junction I mentioned earlier.

[chiph]

The dome lights only work in position 1 or 2 on the ignition switch.

Mercedes has it's own ideas about how things should work. I would check the owner's manual to verify that it's a problem before trying to fix this.

If you don't have a manual, go by the dealer and ask them to get one for you. Under federal law, they're required to give them out for free (this is because the manual details the federal emissions warranty, and the manufacturer is required to tell you about this). I think the lifetime seatbelt warranty also applies.

Chip H.

[grouch]

The dome lights only work in position 1 or 2 on the ignition switch.

Mercedes has it's own ideas about how things should work. I would check the owner's manual to verify that it's a problem before trying to fix this.

If you don't have a manual, go by the dealer and ask them to get one for you. Under federal law, they're required to give them out for free (this is because the manual details the federal emissions warranty, and the manufacturer is required to tell you about this). I think the lifetime seatbelt warranty also applies.

Chip H.

Unlike most cars I drag home (literally) this has all the paperwork from new. I think I'm the fourth owner with the original owner buying it in Indianapolis. I cleaned all the contacts and wires on the secondary junction but it made no difference. I've looked around and found a spot I can mount a 30 amp switch and use it to engage a jumper wire from another fuse position. It's not my prefered methid of repair as I really want to keep this car original as much as possible but with warmer weather, I think the windows really need to open from time to time.

[misterdecibel]

Yeah, you don't want to be one of those lowlifes who has to open their door to use the drive-through window at McDonald's.