Since my new volvo just returned from an extended repair vacation, I am now attempting to fine tune the car.
My rear window wiper needs to be pushed to work. When I turn it on, and give it a little shove, usually to the left, it will cycle for as long as I have the switch on. I have lubed the various exposed rotating surfaces. The motor seems to be fine. It just will not start on it's own.

Thank you in advance.

George
Arizona

 

probably a tired motor. also, there's a slide-rotary-switch thing inside the wiper motor assembly, which is used to tell when its home, this could be gummed up.

not sure the motor assembly is repairable, last one (on a different car) I had out wasn't meant to be taken apart. usual repair method is to find a working replacement, maybe at a junkyard. the tailgate wiper motor typically has 3 wires, one starting a wipe, another thats powered if the car is on so the wiper always returns 'home' if the first one is switched off, and a ground.

another cause of wiper issues is the wire harness that goes over the tailgate hinge, these wires can deteriorate and cause all sorts of flakiness. and, the wiper control stalk switches can wear out and become unreliable.

 

Thank you.

The funny thing is that with the gate lifted, the wiper works perfectly.

I am considering gravity issue. Maybe sprucing up the rotating surfaces and the motor might be in order. I just hate working upside down

 

that could also be a tailgate wiring issue, rather than a wiper motor issue.

 

if it works when you lift the gate, there's a short or loose wire somewhere or a loose mounting screw causing it to act intermittent . find it and wrap it with electrical tape or shrink tubing.

done.

 

Thank you for the advice. I will dive into it this weekend.

 

if its the tailgate wiring over the hinge, thats special high flexibility multistranded wire, and any such electrical tape repair would be sketchy at best, and not last very long.

 

The wires have long ago been rerouted to avoid the hinge.

The only thing which guides me away from electrical is I can nudge the wiper or sometimes slam the drivers door and I can "jump start" the wiper.

Then it runs like new.

 

It turns out that the motor was tired. I finally removed it and discovered that while attached to the battery the motor runs only in certain positions.

Found a nice replacement motor on ebay. The wiper works well on continuous but the interval setting does not work still. May be a relay issue.

Thank you for all of the help.

 

if you bump the manual single shot, does it do a full stroke and stop at home consistently?

 

Yes the blade cycles once when I push the end button on the wiper lever. It returns to home.

 

Mr Pierce

I read your explanation about the 2 hot leads and diode on another thread. I did download a nice primer on the current flow path for each mode of wiper function but have not fully grasped the entire operation. Thus I am interested in the relationship between the single cycle and my intermittent function.

Thank you

George

 

the intermittent relay pulses the wiper power once every N (5?) seconds, and the wiper does a full cycle on its own via the 'return to home' switch.

also, the intermittent relay triggers on the 'wash' function, and powers the wiper for about 3 full strokes worth after the squirters stop.

 

My intermittent mode does not work and the end button cycles the blade only once. My wash function is not working.

Is that a relay issue?

 

let me look up the 1983 240 wiring diagrams to confirm... hm, I only have 84 but thats probably close enough...

looks like the washer pump should run if you hold the button in, even without the interval relay.... so its probably a separate problem. I'd be digging out the intermittent relay, and going over the wiring diagram, verifying things with a volt meter, if it was my car.

 

I'm very happy to have the wiper work at all. That will be on my to do list.

Thank you very much