Electrical:
Wipers
FAQ
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Volvo
Maintenance FAQ for 7xx/9xx/90 Cars
Version 5.0
Wipers
Stop Working: Relay Fix. [Query] My wipers have been stopping
intermittently the last few days. I have checked the fuse (it's on
the same one as the horn) by honking the horn. They wipers run fine and
then all of the sudden they stop. Then inexplicably .... they start
up again. What are the troubleshooting steps from simplest and cheapest
to more complex and costly. [Response: Don Foster] Find the w/w relay
and resolder it. The wiper relay is in the back row of relays on the main
relay tray, third from left. This may not be the "fix" -- but
if you resolder (instead of replace) then it'll cost you about 20 minutes
and $0. So to start, it's simple and cheap.
Wiper
Motor Problems. [Symptom:] Whenever I use either my intermittent or
low they work for maybe five minutes and start to slow down until they
stop. The weird thing is that my high wiper setting seems to work fine.
[Fix:] I had a problem like that and found that the motor brushes were
marginal. I guess the low speed stress them more and tend to over heat
and bind in the holder... at higher speeds the momentum is a help and also
lower current flow and less heat generated... in a nutshell replacing the
brushes cured my problem..
[Related Comment:]Not sure about the 740,
but the 240 equiv. failure mode is usually due to the permanent magnets
inside the motor shell separating from the case due to rust infiltration
on the glue. They shift and drag on the rotor, as well as mis-align the
field. Can be repaired quite easily, if that's what it is. You can replace
the brushes same time, if needed, and if you can find some, but I found
my 1984 original brushes were fine. (Stretch the springs a bit if the brushes
have shortened). I found my high speed was slower than normal, and low
was very slow. And then it stopped.
[Another Comment:] Assuming 740 is not
too different than the 240, fix involves pulling the motor out, (you have
to disconnect the linkage clip under the dash), and open the shell. Careful
to not drop the magnets, they are ceramic. They have a tendency to follow
anything ferrous, I smashed one once when it followed a screwdriver I had
picked up and it accelerated right off the bench. Clean up the rust, and
epoxy the magnet(s) back in. Note position and orientation when you remove
the magnet. Buff up the brush contact segments on the armature if necessary,
lube bearing and reassemble. Brushes are a bit tricky to compress while
inserting the armature, a loop of thread and masking tape works great.
{Another Comment:] Also: first you may
want to check the ground connection; my 745 had a bad ground to the wiper
motor, which consisted of a jumper across the rubber-mount at the driver's
side. I wired in a new ground and voila.
Wipers
Are Slowing Down. [Query:] I noticed my wipers to be sweeping
slower than usual lately, and a whirring sound to be coming from the wiper
motor. There was even an instant that the wipers would not sweep, before
it suddenly came to life and began to sweep slowly. Fuse was OK. Windshield
was very wet with rain. Wiper rubber strips are 3 months old. Is my wiper
motor about to die? Or should I squirt some WD-40 somewhere to "loosen"
up the motor? [Response: Richard Klasic] It's hard to describe
but the wipers are mounted on the shaft going through a bushing.
After years of usage. this bushing becomes dry and corroded making the
wipers move more slowly until they freeze completely. You need to take
out the shafts and polish them gently with sandpaper and then lube the
shaft with a grease that doesn't go away with water. You can always
unhook the motor from the ball joint to the wipers and see if it runs fine.
I bet it does. This was the case on my wipers on the old 760 I had.
It really squeeked when running. And after 15 minutes hammering at the
tap with a plastic hammer and lot of WD-40 it finally came loose.
After my operation WOW the wipers were dead silent and swept like lightning
over the windshield
Wiper
Arm Removal. [Tip from Sheldon Fast] There is a plastic
black cover over the end of the shaft, when you take this off, you will
see a nut on the end of the shaft. Same for front and rear wiper
arms.
Rear
Wiper Motor Failure. [Various diagnostic tips on rear wiper motor failures]
1. The reason for the constant failure
of these motors is because the linkage going out through the rear window
needs greasing every year. This takes a salt pounding all winter and seizes
up, over-stressing the motor and burning it out. Remove the rear wiper
arm, pull the rubber protective cap, remove the tiny C-clip and push the
linkage into the car. Clean the hole, sand the shaft, grease with a synthetic
grease (still viscous in the cold weather) and reassemble.
2. My rear wiper motor (1985 740
wagon) kept going slower and slower and I ignored it (bad move).
It was the pivot bearing (white metal?) that had just corroded to the point
where it was freezing up and eventually burned out the motor. Strangely
enough, my independent dealer cleaned up the "bearing" and reinstalled
it (and a rebuilt motor, too). My first instinct would've been to
replace the bearing with as new one but, so far, so good. So, if
you're fiddling in those parts, check it out.
3. I pulled the entire wiper motor out,
took it apart, and (believe it or not) everything worked great after I
put it back in. Problem was tarnished electical contacts on the brushes
and commutator of the electric motor. I polished them up with a piece
of emory cloth, and it's working great now. [Editor's tip: prevent this
by operating the motor every few weeks.]
Rear
Wiper Motor Won't Park. There is only one way to get the arm to rest
in the correct position, and I'll try and explain it here. First, remove
the wiper arm from the shaft, this is the last part to go back on. Now
turn the key to the "on" position and start and stop the motor so we are
certain it is in it's rest position. Remove the inner panel. On the motor
is a ten millimeter nut holding the short linkage piece of the wiper arm
to it. remove it and pop off this short piece. turn the short piece until
it is parallel to the long linkage arm it is attached to, not outwards,
but inward, so the total length of the linkage is not longer than the long
piece. (they're now overlapped) Now pop the short linkage onto the motor
and put the nut on. This requires deft hands as the nut is exactly between
the two pieces of linkage. don't worry, there's room. Before you snug nut,
ensure the two linkage pieces (the short and long) remain perfectly parallel.
Tighten. put the wiper arm back on (mine is a 745, so the arm rests to
the driver's side, make certain you remember where yours rests)
Front
Wiper Failure to Park. The wiper motor gets power from two sources.
One is from the switch on the stalk. The other is from the battery via
the ignition switch, but in series with this path is a switch internal
to the wiper mechanism which opens up once per cycle. If the second circuit
is functioning, when you release the stalk switch, the second circuit still
carries current to the wiper motor until it reaches the wiper position
where the internal switch opens. At this point, if the stalk switch is
disengaged, the wipers park. If the second circuit isn't working, either
because of a faulty wiper park switch (inside the wiper mechanism) or because
the external wiring isn't delivering current to this switch, then the wipers
park immediately when you shut off the stalk switch, as you describe. First
thing I'd check is the wiring.
Windshield
Washer Jets Don't Function.
Clogged Washer Jets. [Query:]
I have noticed that my windshield cleaner jets have clogged up over the
years, and one is now in service, but is spraying over the car. How do
I go about fixing this?
Function. [From GN]
So here is how it works: The tiny green T in the washer hose is a
overpressure-relief valve. If the nozzles are blocked the pump will
deliver the water back in the reservoir. The second T with red cap
under the middle of the windscreen is a backflow-suppression valve.
It will keep some water in the lines to be ready. Otherwise it will take
1-2 seconds to deliver water to the nozzles.
Nozzle Repair. [Response
1: Dennis Hamblet] The best tool for cleaning washer nozzles can be bought
at a welding supply house and is called a tip cleaner. It consists
of a graduated series of very small round files that can be fitted into
the jet and remove the deposit which is generally mineral deposits.
Jets may be adjusted by inserting a pin (or a tip cleaner) into the jet
and rotating it into proper position. [Response 2: Michael
Brown] Do you have access to compressed air? I took off the hose
at the plastic connector under the hood and put a compressed air nozzle
in the end of the hose. It blew out the blockage and all is well.
[Response: Stephen Ringlee] Use a sliver of thin steel wire
to clean out tip deposits and buy an in-line filter from IPD or Volvo to
keep debris from clogging the lines. A needle can be used to adjust
the aim. [Response: Jack Reed] Clean them with the finest wire
that will fit in the hole without binding. Prevent the problem
in the future by buying a lawn mower sized gas filter. Fits
perfectly into the main feed line from the pump before the T. Just cut
the line in the best spot for the filter and remove a filter sized section.
Change it every few years and you should be fine. Considerably cheaper
(~$1.50) by the way, than the $5 IPD wants for the same thing. [Response:
GN] I took out the nozzles and put it in an ultrasonic-cleaner with
the regular vinegar ( it has only 5 % ) and some drops dishwasher liquid.
Approximately 10 minutes each side then rinse it and spray with teflon
oil and put it back in the hood.
Washer Filter. [Tip: Stefan
Schader] I found that the windshield washer fluid bottles contain sometimes
small plastic shavings which clog up those nozzles and the fluid tank filter
does not stop them. To prevent this, I put a small in-line fuel line filter
in the washer fluid line a few years ago. Voila! no more problems since
then. (Editor's note: this style of filter is also sold by Volvo, IPD and
NAPA. [From GN:] NAPA 3011 BP - $ 2.70 has the right connector size
to fit in the hoses . )
Windshield Washer Check Valve R&R.
[Tip from John Kupiec ] One other possibility on clogged windshield washer
jets... If absolutely no fluid squirts from the jets, the problem
may be a bad check valve in the piping between the washer pump and the
jets. The check valve looks like the little brother of a PCV, and
it sits at the point where the one tube from the washer pump splits into
the two tubes that feed the jets. To test the check valve: Disconnect the
tube that feeds from the washer to the check valve. Try the washers. If
you get a stream of washer fluid, you know the pump is okay. Next, reconnect
the feeder tube to the check valve, and disconnect one or both of
the tubes leading to the jets. Try the washer. If you fail to get a good
steam of fluid from either of the two tubes leading to the jets, the check
valve is bad. Replacement check valve run less than $10. [Tip from Larry
Jacobson:] Thanks much to the Brixters who suggested cheap and quick solutions
to this windshield washer problem. It turns out that the nozzles
where somewhat clogged and the little black and red distribution check
valve had accumulated crud. For those who may not have had the pleasure
of messing with one of these, the red cap can be pried off with a knife
blade. I boiled the two parts in water for awhile and then took a
needle and cleaned the narrow groove between the black diaphragm and the
red cap (together they form a clever check valve). ...slapped it
back into the car and voila! clean windshield. Saved 8 bucks.
[Caution from Jordi Mir :] I had to buy a check valve, because FIRST
I cleaned and fixed it as described above... without result, because the
thin rubber seal inside the check valve was dry and finally broke. If broken,
or if a single "T" fitting is put in place with no valve inside, water
could leak back down to the headlamp washers or to the electric pump and
reservoir... So, IF the rubber seal inside the valve is dry or broken,
my experience is to go to a new check valve.
Washer
Pump Rebuild. [Query:] I have an 87 745 and its rear washer pump is
dead. I never added anything but standard washer fluid. Is this pump
a known failure item in high mileage bricks of this vintage? It worked
fine until I added the orange colored fluid booster additive sold by IPD
and other sources curious about replacement cost and difficulty... [Response:
Robert Haire] Before trashing them, take the pump out and unscrew the tiny
screws in the bottom. You will often find the crude from old washer fluid
has precipitated and clogged the gears. If you clean them out, they might
start running fine again. I have salvaged several of mine this way and
have never had to buy one.
Removing
Cowl Screen for Windshield Wiper Motor Access. [Tip from Richard
Klasic]
1. Remove the wiper arms
2. Remove the rubber trim around the wiper
axle
3. Open the hood
4. Locate three screws (the 10mm spanner)
one near the fenders and one in the middle
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5. Gently lift up the cowl panel, which
has some hooks at the windscreen so you have to wiggle it some. The cowl
panel is the painted chassis part where the air inlet is located. Under
this cowl panel, the wiper assembly is found. It can removed by unhooking
the electrical socket and unscrew maybe 2 screws.
Volvo Maintenance
FAQ for 7xx/9xx/90 Cars
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