240 Power Window failure

Hi all,

I'm trying to diagnose the power window failure in my sister's 1990
240 wagon.

The symptoms:
1. With little warning all windows have stopped working
2. Replaced fuses #10 and #12, sanded all contacts
3. Checked grounding screw under dash (secured)
4. Voltmeter indicates 0 current across fuse 10 which increases to
+-12v when switch applied
5. Voltmeter indicates -ve current across fuse 12 which is unchanged
when switch applied

My diagnosis was that the relay had failed but don't know how to test
the relay. Furthermore I hoped to pull the relay from my 1983 240
Turbo as a temporary fix but am not sure the relays are
interchangeable. The relay in my car ('83 240t) looks like this:

http://63.150.115.104/CommerceGateway/pictures/Volvo J-Pegs/1235893.jpg

Is the relay in the wagon necessarily the same? I pulled the centre
console off and according to Haynes there are only 4 relays in there:
1. Overdrive Relay 2. Door Unlock relay 3. Door Lock Relay 4. Power
Window Relay. By process of elimination I determined that a grey
plastic relay (whose removal did not affect locks or OD) must be the
window relay.

All I guess I need to know is are my assumtions correct and am I on
the right track? If so I will pull this plastic relay and take it to
the dealership for testing/replacement.

Thanks lots,
blurp

 

Hello again,

I have managed to determine that:
a) The plastic relay I was muddling with in the 1990 wagon was, in
fact, the AC control relay (thanks to FCP Groton for the great
pictures) and that the window relay should be the same for all models.

Great.

The remaining question then is, given the voltmeter results I
received, is it a reasonable assumtion that the relay has failed?
Should the voltage across fuse #12 not change when the switch is
employed (as does on fuse #10)?

Or can I start to look for breaks in the wire somewhere?

Thanks a bunch,
blurp

 

It could be the relay, but they very rarely fail. You could check the
connector on it as it may have oxidized, but the most common fault is the
window switch itself, and one bad switch can render the windows on both
sides inoperable.

 

Note, using a voltmeter isn't the best way to check an automotive
electrical circuit, it doesn't provide enough of a load, so you can get
instances where bad connections pass a test with a voltmeter's load, but
won't pass enough current for the device you're trying to operate. A
better tool is the cheap old test light with a 3w bulb. (An even better
tool would be to connect a brake light bulb across your voltmeter test
wires.)

Since you've found the relay, it's easy to check. There's 4 wires
connected to the relay. There's a pair of terminals that are opposite
each other that are parallel, these are the control terminals, the ones
that make the relay click. One of these wires should be grounded
(black?), the other connected to the fusebox to a fuse that gets power
through the ignition switch. (Probably your fuse 10.) The other pair,
with terminals perpendicular to each other are the power wires. One is
connected to the fuse that's live all the time (probably your fuse 12),
the other goes to the driver's switch panel (red as I remember on my
'83). If you just connect these last 2 wires together you take the
relay out of the circuit. If everything works now, and the control
wires pass the test from above then you need a relay. Otherwise, look
for the red wire at the switch panel as see if it has power. (I'm
thinking your problem is broken wires where they flex on their way into
the door.)

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

I checked the car out again last night and realized a couple of
things: I can't find the relay (it's not bolted in the same place as
my '83 240 which is right behind the grounding screw under the change
tray) and the accordion the wires pass through in the driver's door
hinge had been split, worked on, and repaired in the past.

(Late breaking My sister revealed that the windows briefly
responded when the driver's door was slammed)

Upon removing the rubber accordion I found one black wire to have a
crimp-connector on the end of it but not connected to anything. All
the wires there were covered in what appears to be butyl and some look
spliced with non-matching colours.

So first off I'll pull a switch from a rear window and try it in each
of the 4 connectors under the driver's switchbox.

Then, since I cannot find the relay, I'm going to pursue the damaged
wire to its logical conclusion. There is no slack in the wires so I
need to take the door panel off but I hope to find there either a
matching bare/disconnected wire OR a spot where the black wire may
have been grounded.

As for the test bulb I have one that was given to me by an electrician
but I think it only operates under household voltages.

Once again, great tips from James S. and Mike F., I'll check these
things tonight!

Thanks very much,
blurp

 

Well I got the door panel off and got a better look at the wiring and
found the black wire that was disconnected is the ground that runs to
every switch in the cluster. I also found that the split in the
accordion was made so that someone who worked on the car earlier could
insert some "mechanics employment insurance" in the form of a 3-inch
extension to the wire spliced in with crimp and heat-shrink at either
end. The wire broke at the crimp. I wanted to run a new length of wire
from the break to the switch but I was worried that the guage or
resistance of the wire was something specific and all I had is some
old lamp cord so I affected a repair with a houshold marette wound
tightly in electrical tape and about 3 feet of (what else?) duct tape.

And now it all works again!

Thanks again for all the advice and helping me narrow down the search.

Hope you all have a Happy Canada Day / 4th of July weekend (and if
you're not in Canada or US make up a holiday and stretch that
weekend)!

blurp

 

Well I got the door panel off and got a better look at the wiring and

Wow! I just fixed the same problem last weekend. Sorry I just dropped by
here now...
The green wire was broken in the accordion and the insulation of two others
were defective also (but the wires were not broken yet) Result: The window
on the co-driver side could not be operated.
It took me all day to find the error - with a multimeter an a lot of home
made hand drawings of the wiring. Maybe i should change all of the cables to
the doors. They don't seem very flexible anymore.


/Jakob - Denmark, Europe (having a week off now and going to the Copenhagen
Jazz Festival)