On my 88 240 wagon, my rear wiper and washer has now gone from working on occasion to not working at all...except for when I first start the car: the wiper gives one swipe and stops. Turning the switch on and off does nothing. My front wipers and washer work fine. The fuse is good. Is the problem the wiring harness that travels through the tailgate, the wiper motor, or the stalk with the wiper controls? Or something else? Thanks in advance.

My money is on a bad ground.

My '89 developed tailgate electrical issues about a year ago. I found the hinge harnesses were OK, HOWEVER: the black ground wire that ties the body side of hinge to the tailgate side was torn. Same wire was torn on left and right side of car. You can see those ground straps from outside of car with tailgate shut, just step up on bumper or get up somehow. Look down into hinge's groove and you can see the black wire.



I screwed a ground wire into the body frame, near where the tailgate struts are anchored (both sides of car). I ran the wires down into the holes in the sides of tailgate and fished them out at the bottom. From there the wires go towards the center where the 'factory' ground screws are. That fixed it.

Wife's car developed a similar ailment a couple months ago. Same routine over again. Problem solved.

When something electrical doesn't work properly when asked, and something else works instead (as in your wiper working when not asked), it's usually a bad ground. The thing with the bad ground is grounding via the one that works at the wrong time. It's working because it's carrying the other thing's current to ground.
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Sven: '89 245 NA, 951 ECU, expanded air dam, forward belly pan reaches oem belly pan, airbox heater upgraded, E-fan, 205/65-15 at 50 psi, IPD sways, no a/c-p/s belt, E-Codes, amber front corner reflectors, aero front face, quad horns, tach, small clock.

The wiper motor has certain connections that enable it to park the blade in a specific place after the stalk switch is turned off.

The motor has a ground, a switched (from the stalk) hot wire, and a hot wire that is off when the key is turned off.

There is a little switch in the motor. It allows power to the motor from the "always hot" wire, so that when you turn off the stalk switch, the motor can continue to run until a bump on the motor shaft opens that little internal switch. The bump is located to have the blade stop in the park location.

Do this - watch the wiper when starting the car. Hit the start position just a wee bit, not enough to start the engine. Does the wiper make its one cycle? Does it quit part-way through?

Do it again but being sure that you are not stepping on the brake. That 3rd brake light puts power into the cargo door, and its wire may come through that same right side hinge.

Do the ground connection cleaning. A bad ground can cause weird things as current wants to flow and if the ground doesn't allow it, it will go somewhere else.

With the cargo door closed, look down into the hinges. The wires are visible, and you will see whether they are damaged or not. The route into the door is through the right side hinge (look at both sides anyway). That's for the two power wires, the ground wire may differ. The motor is grounded to the door, so the door should have a ground wire to the main body of the car.

Good Luck,

Bob

:>)

PS: The book you need is Volvo Service Manual Section 3(39) Wiring Diagrams 240, 1987-1988 TP 31076/1 3000.04.88. I have that one, there may be updates. Call 1-800-25-VOLVO or visit http://volvo.techno.org.pl/wiring-diagrams.html or wwww.volvotechinfo.com. Worth the money.

Wow thanks bob...I've been so busy I forgot about the wiper until we had our torrential rain yesterday. I will follow your very thorough guidance this weekend and see what results;)

Very likely the harness that goes through those hinges at the top - lots of exposure (happens every 10 years).

thanks for that website, it's a great resource and I bookmarked it. much better than the Hayes manual. Unfortunately, I struggle with schematics (I have to deal in 3D :). I was kind of hoping that someone could help me deduce the likely source of the malfunction based on the fact that the wiper stalk operates the front wipers fine, but will not operate the rear wiper or washer...yet whenever I start the car, the rear blade moves once, and that's it (even though the rear wiper switch is in the off position. Sounds to me like current is reaching the motor in order for it to move when I turn on the car (and may therefore mean the wiring harness is okay). So, not being very mechanically inclined, and given what I do know about the situation, I'm trying to figure the likely source without tracing wiring, etc. Any suggestions?

it sounds like the stalk on the steering column which activates the wipers has a bad switch for the rear wiper.

you can test by applying 12 volts directly to the hot wire in the tailgate which goes to the motor. if it works it isn't the motor.

your problem lies in a corroded ground connection on the tailgate which serves the wring for the motor.

it is easily visible if you open the tailgate and remove the fuzzzy fabric cover. follow the wiring on the motor (right side) and you will see several grounds to the gate. i forgot which one exactly but unbolt all of them and use some steel wool or light sandpaper and make the ground and connect shine, add a little dialectric grease and rebolt.

i suspect this will solve your trouble.

the way to test this theory beforehand is to take a multimeter and test the voltage going into and out of the motor.

Great, I can handle that. I'm just going to do it without testing it first (I don't have the nec. instrument, though I obviously need to get one). THanks a bunch for the step by step!

This may help you diagnose your problem.

http://volvo.techno.org.pl/wiring-diagrams.html