How do I test a power window switch?

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jeniax - 03 Oct 2008 08:22 GMT

My 98 Mitsubishi Galant (4 dr, with the auto-down feature) has
developed this problem-the driver’s side window (only-all others work
fine, both at the master & at each window) will not go down. in
theory, it will go up, but since it’s already up the whole way... It
started out that it would hesitate before going down, just a second or
2 at first, then eventually it could be 10 minutes after you pressed
the button & then suddenly it would go down, until recently it quit
working completely. Never had a problem going up, though.
I took it out & opened it up - everything looks pristine, a little bit
of green staining, but not near that switch. I was thinking about
just replacing the whole thing, but I wanted to verify that it is the
switch & since this thing has the computer stuff in it, my husband is
unsure of how to test it (just used to the older stuff & all) No
sense wasting $ on it if it’s a relay or wire or something. We did
clean up the corrosion, but I doubt that was the issue. I have also
read the posts about power window switches & I plan to go pop it back
in today & try holding the down button & slamming the door, but my
luck usually isn’t that good!! :roll:
He plans to come home tonite & fiddle with it, but I figure knowing
how to test it is better than the 2 hours it’ll take for him to figure
it out on his own (it’s a girl thing.) So, can anyone explain how to
test it?

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Bob Shuman - 03 Oct 2008 16:35 GMT

You can test the switch using a common digital multi-meter. Remove the
switch connections and connect one probe lead from the DMM to each contact
terminal. Then set the DMM to the Resistance/Ohms range and check the
resistance. Then toggle the switch to the other position. When "off" the
meter should read very high ohms (near infinite... definitely in the
megaohms range). When the switch is toggled "on" the resistance should be
very low ... say no more than a couple ohms ... maybe 6-10 at most depending
on the accuracy of the meter.

Another test here using the same meter set to "DC Voltage" range is to
measure the voltage from the switch common terminal (incoming) to the
vehicle negative battery/chassis ground. You should see full battery when
the Accessory switch is on and the window is enabled ... around 12V. Then
measure the other side of the switch to ground while the switch is
depressed. You should also see similar voltage. If you do, then the switch
is good and you need to look at the wiring from there to the window motor,
or possibly the window motor itself needs replacement.

Good luck.

Bob

> My 98 Mitsubishi Galant (4 dr, with the auto-down feature) has
> developed this problem-the driver's side window (only-all others work
[quoted text clipped - 18 lines]
> it out on his own (it's a girl thing.) So, can anyone explain how to
> test it?

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Dex - 04 Oct 2008 03:53 GMT

    Hi,
        I would be hesitant to expect 12V at the switch terminals as the
windows are probably controlled by the ECU. The switch may only provide
a trigger pulse for the window activation. But you could use the switch
measurements to work out which contacts close to get the window to go
down and then short the wires to make sure the switch is not faulty.

    cheers,
        Dex

> You can test the switch using a common digital multi-meter. Remove the
> switch connections and connect one probe lead from the DMM to each contact
[quoted text clipped - 40 lines]
>> it out on his own (it's a girl thing.) So, can anyone explain how to
>> test it?

Reply to this Message

jeniax - 12 Oct 2008 02:22 GMT

Hey, just wanted to say a great big THANKS! - I printed out your reply
for Dan & he said it was just great, made it very easy for him. He
had to go borrow his Dad’s digital tester, since all we have is the
non-digital kind, but having your instructions made it a breeze.
When he tested my switch, every other switch on it read normal except
for when he tested the driver’s window switch. Going up-fine, going
down-almost nothing.
Now, I just saw the second reply today--that makes me kinda nervous.
I haven’t bought the new switch yet-was still browsing eBay for the
best deal on a used one. I will have to make Dan read it when he gets
home tonight, as it’s greek to me-the whole digital tester was new to
my limited automotive experience. I’m pretty sure he did both kinds
of tests you described. Can we still be confident that a new master
switch will give me back my ability to use drive-thru windows?? (The
lack of this ability is WAY more annoying than one might first imagine
& it’s about to get cold again around here soon!)
& Once again--Thanks, :D so much!, for those testing instructions!
Je

> You can test the switch using a common digital multi-meter.
> Remove the
[quoted text clipped - 73 lines]
> explain how to
> > test it?

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Bob Shuman - 12 Oct 2008 14:54 GMT

Jen,

If the old switch tested bad with the meter, then a replacement switch
should definitely fix your problem. Hopefully you can purchase just one
switch. If not, then it may be expensive or you may need to find the
replacement at a salvage yard. Good luck and thanks for the reply.

Bob

> Hey, just wanted to say a great big THANKS! - I printed out your reply
> for Dan & he said it was just great, made it very easy for him. He
[quoted text clipped - 92 lines]
> > explain how to
> > > test it?

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jeniax - 13 Oct 2008 22:22 GMT

OK, I just bought a used master window switch on eBay--$24.99
including shipping--that is the whole thing that sits in the D side
door, all 4 window switches, door lock, & rear window lock. Once it
gets here & we get it in, I’ll come back & post whether this fixed my
problem.
I figure some other person might have the same issue, & find this
thread in an archive search--might as well make it show the final
outcome! Plus, I can play ’test subject’ about buying used parts for
real cheap on eBay--see if I got a deal or wasted $25 bucks & end up
needing to buy another one. I mean, $25 bucks is CHEAP--I realize
that I’m taking a chance here, but the car is 10 years old--thats
about all its really worth spending to fix little non-mechanical
problems on it!!
Oh yeah, holding the ’down’ switch & slamming the door had no effect
what-so-ever, but my 14 yr old son had great fun doing it over & over
until I yelled at him to knock it off..

> Jen,
>
[quoted text clipped - 147 lines]
> > > explain how to
> > > > test it?

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Bob Shuman - 13 Oct 2008 23:06 GMT

Good luck, Depending on the design arrangement, sometimes you can swap out
an individual switch if you should find that one of the "new" ones is
defective. I've found many parts at considerable savings via Ebay. I've
actually seen where a brand new, exact same part is as much as 80% cheaper
than at the dealer. Sounds like you did good!

Bob

> OK, I just bought a used master window switch on eBay--$24.99
> including shipping--that is the whole thing that sits in the D side
[quoted text clipped - 164 lines]
> > > > explain how to
> > > > > test it?

Reply to this Message

jeniax - 17 Oct 2008 01:22 GMT

Hey, final outcome update here--I HAVE A WORKING WINDOW AGAIN!!! my
new (used) switch came today, I put it in , & voila!-problem solved.
I am doing the happy dance--I don’t know about ALL the people selling
used car parts on eBay, but I give the guy I bought mine off of high
marks

> My 98 Mitsubishi Galant (4 dr, with the auto-down feature) has
> developed this problem-the driver's side window (only-all
[quoted text clipped - 22 lines]
> take for him to figure it out on his own (it's a girl thing.)
> So, can anyone explain how to test it?

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Bob Shuman - 17 Oct 2008 02:38 GMT

Jen,

CONGRATULATIONS on fixing the window and on saving yourself a lot of money
in the process! I'd suggest that you use a portion of your savings to buy a
nice Digital Multimeter or some other needed tool for next repair job.

Bob

> Hey, final outcome update here--I HAVE A WORKING WINDOW AGAIN!!! my
> new (used) switch came today, I put it in , & voila!-problem solved.
> I am doing the happy dance--I don't know about ALL the people selling
> used car parts on eBay, but I give the guy I bought mine off of high
> marks.

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