Tailgate Wiper Motor Install Question

[imaV70Rdriver]

More than a year ago, my tailgate wiper stopped working. I also started getting "multiple bulb failure" messages, which were cured, for a while, by replacing the appropriate 7.5 amp fuse in the dashboard fuse panel. That worked until the tailgate was opened and closed a number of times. As so many others have experienced, I found numerous wires running through the tailgate hinge area in need of repair. Ten of 11 were damaged and six were completely severed, and yes, all three yellow ones.

I soldered it all back together and tested all wires for continuity. But the wiper still didn't work, even though there is power to the wiper motor connector.

The relay clicks on and off properly, and tests correctly with a voltmeter while switching.

There had been a blown (wiper) fuse, a 15 amp, which at some point, I substituted with the only fuse I had left, a 25 amp. Hmm. I know.

I then checked the motor itself. I popped off the black plastic cover protecting the circuit board, and found a copper ribbon had failed.

I tried to repair this by carefully soldering a length of stripped telephone wire.

With the wiper motor mounted and no wiper installed, I turned the wiper on and it worked in the intermittent position, seemingly fine, so I switched to constant, where it sounded unhealthy, until about 30-40 seconds later, it stopped. When I took the circuit board cover off again, I found my attempted repair failed in a big way.

So I bought a new motor, and before I install the thing, I would like to know how to properly test, and be sure the proper function of the circuit to the motor connector. So as to not to naively destroy the new motor.

This is where I'd like some clarification please.

There are three wires, black is ground, white is constant power (fed from pin 3 on the relay), and if I'm correct, the yellow wire signal (from relay pin 5) is controlled by the stalk mounted tailgate wiper switch. If the switch is down, the the rear wiper should run constantly, and if switched up, the wiper is intermittent. The power setup is such that the connector should "always" be sending power through the white wire, to the motor circuit board. The motor will not run in this case. There needs to be a signal from the stalk switch, which comes via the yellow wire, either sending a constant voltage, or an interrupted voltage, depending on whether the switch is down or up respectively. This is what I think is going on. Do indeed correct me if I'm wrong, it's the reason for this post.

I will put in the correct 15 amp fuse before I connect the motor.

Concise constructive input welcome, thanks.

[abscate]

What year model car is this?

Find the wiring diagrams in the web and post a pic of the circuit if that doesn't clarify the assignments

I'm a bit confused because the Motors attach with a plug that will only attach one way.

[imaV70Rdriver]

Thanks abscate, 2004 V70R. Where would I find a wiring diagram showing the rear wiper circuit? Anyone have a link? Or can someone tell me how to locate it using VIDA2014D?

(I find VIDA not particularly intuitive, and frustrating when you know the info you seek is definitely there, you just don't know Volvo's specific term to use in the search. Is there a decent tutorial somewhere? Or operators manual?)

There is no issue plugging in the connector. It does only connect one way.

I want to be sure I don't fry the new motor, due to something in the circuit upstream not working properly. How do I do that?

In my original post, the paragraph after "This is where I'd like some clarification please." is where I need help.

[abscate]

We don't host the wiring diagrams here, by legal agreement with Volvo.

manualslib has most every public manual online, though.

Im not an expert on the Volvo system but most upstream stuff from the components is module controlled, so if something goes wrong, the module shuts down.

The stressed part of the wiper system is the motor of course, so I would be 99.9%confident that is your failure and not worry about the rest.

[imaV70Rdriver]

abscate, what you said makes good sense. I installed the wiper motor and wiper, and it all works perfectly well. Your 99.9% confidence was much appreciated. Thanks.

[abscate]

abscate, what you said makes good sense. I installed the wiper motor and wiper, and it all works perfectly well. Your 99.9% confidence was much appreciated. Thanks.

Im glad that worked because I made that confidence level up. I do that 99.44% of the time.

(seriously, I was pretty sure you were overthinking it)

[Rattnalle]

I agree with over-thinking. Mostly the wiper motors stop working because the axle siezes. When the axle won't move the motor will draw too much current blowing the fuse. Eventually you might end up burning the motor or even more commonly the motor will destroy the plastic gearing inside the motor. The rest of the electronics seem to be pretty solid.

[kolis]

Could you send me full photo, please? My problem is visible on the attached picture.
Thank you in advance.
Best regards
kolis