I have an ML320 1999 and the driver side window switch is bad. The window
switch controls the downward motion but when I lift up on the switch nothing
happens (not even any light dimming). If I depress the switch again (with
the window in the open position) there is a dimming of the lights so I know
there is power to the switch and window. It appears the switch contact(s)
to allow the window to go back up are bad.
We just got 18 inches of snow here in New England and this causes a bit of a
I took out the console box and disconected the electrical wiring plug for
the window sitches on the driver side. There are 7 wires into this plug.
If I can figure out which one, or two or three, go to the driver window I
can try and short these together so as to make the window go back up - then
I can take the car in for repairs. I can't determine which wires to use
though. I've been tryting to short out two wires but nothing happens which
leads me to believe I probably need to work with three wires.
Any ideas on which wires/contacts in the plug I could short or contact
together to get the window back up? The wire harness/plug seems to supply
power and control both front/back driver side windows as well as the master
lock/unlock switch. There are two white wires in the harness of 7 total.
You need a new switch pack, and it sounds like you have already pretty
much stripped it out, can you not just buy the part and then fit it at
If not then you can email me your chassis number and I'll have a look
at the appropriate wiring diagram for you....
This is a very common problem on pre-2002 ML's. The only permanent solution
is to replace the switch assembly. If you are out of warranty, you might
still get it replaced by MBZ if you use the phrase "goodwill". Of course if
you're under warranty, they will replace it for free. In fact, Roadside
Assistance used to carry spares. If you want to DIY, then I suggest just
buying the part. It's a 30 minute job at best and the part is very
inexpensive (I've heard it's about $40 for the whole unit). In the mean
time, if you can't make it to the dealer, look here for detailed
instructions on how to repair the contacts yourself:
Excellent guide to the removal and repair of the switches.
This was my experience in my 2000 ML320. At the time, my car was about 2
years new. I'm with my wife and sleeping 2 year old daughter at about 7pm
on a Sunday night, leaving Lake Tahoe via I-80 west from Truckee heading
home to Marin. It's 17 F outside. I had noticed the increasingly more
frequent intermittent power window spasms and said to myself, I should try
not to use the window and open the door instead. If you don't know that
route, there is an agricultural check station on 80 at Donner Lake. I pull
up and absenmtmindedly put the windiw down to tell the attendant that I
don't have any produce from out of state.. Now the window isn't going up,
no chance. Thoughts of turning back and worrying about it the next day
seemed appelaing but it was just as cold back there and about 15 miles back
to the condo and I had to work the next day. I thought of how I might
safely cover the window to make the 3 1/2 hour trip. The whole time
thinking about my sound asleep daughter. I pull over and call Mercedes
roadside assistance. The rep tells me the nearest service center is 100
miles away, and he would have to call a technician to meet me there. I was
impressed by the offer but that wasn't the solution. I explain my situation
and the tech on the phone says he isn't supposed to tell how to do this but
the solution was to break the switch by pulling up hard on the lever. Hard
enough to pull it off completely, once off, the switch body can be removed
and you can see inside and look at the copper contacts. There are 3 of
them, he tells me to press on the middle contact with a pen or toothpick or
something like that. I use my ever present ball point pen and up goes the
window. We're back on the road in less than 10 minutes. The next day I
call service at the dealer, make an appt. to bring it in, they give me a new
E-class to drive for the day and it's fixed. I've had no problem with it
since. My point is, the switch may been a bad design but the service makes
up for the occassional imperfections. A note on the remedy, they replaced
the window switches with the ones they use in all of their other cars with
the '02 model year.
I have heard others mention this "emergency fix". I tried this on mine and
ended up causing the entire switch assembly to break away from its mount and
fall down inside the console. When I called for service, I was told the
switches were backordered, and this was why I tore into them myself.
I wish that I could say the same. I have received nothing but horrible
service from my dealer, and since there's only one in town, it's not going
to get any better.
Yes, I believe the contacts are the same, but I do not like the location of
the switches in any of the new models. I prefer the center console mounting
of the pre-2002 ML and the older cars. Starting in 2002, they moved the
ML's switches to be on either side of the shifter to make room for a
cupholder. In the C and E cars, the switches are mounted very
inconveniently on the lower part of the driver's door. The good thing is
that they are auto-up/auto-down on all windows now.
Keep in mind that this fix is only temporary. The contacts will most likely
become misaligned again. The real solution is to get a new window switch
assembly from the dealer that has redesigned contacts. If your truck is
recently beyond the warranty, you might try getting them to replace it as
"goodwill". If you have to purchase a new switch assembly, I believe the
cost is less than $50. Using the directions noted above, replacing the
broken assembly with a new one is very easy. One thing I'll note about the
directions is the single wire connector may not exist on earlier models
(pre-2000). That wire allows user programming of the auto-lock feature.
Earlier ML's did not have this capability and thus do not have the wire
(only the dealer can program the auto-lock on those).
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