2006 V70 rear Wiper issue

[cn90]

I need to go to junkyard to find a rear wiper motor.
Virtually all junk yards remove battery from the car.

However, I hate to buy and return it. Is there anyway to test the rear wiper motor at junk yard?
Such as using 9V battery just to see the motor makes any noise?
Does anyone have the electrical circuitry of the rear wiper motor?

[abscate]

You could test it on your car battery at the junkyard?

Here is my 2005 circuitry, I think it is the same.

[cn90]

Thanks abscate...

The problem is: once I buy the item and take it to the parking lot, it is considered "sold" and done.
Unless I buy the "warranty" lol.

I guess I can use the battery inside the junk yard counter.

[cn90]

Thank you all for posting the electrical diagram for REAR wiper motor, but that is for 2005-2007 V70.
For 2001-2004 model, I played around with it during the weekend...

I have not opened the plastic cover (at the hinge) and peeled the sleeve back to inspect yet (no time bc of work). So far:
- All functions in the tailgate (license bulbs, tailgate latch, 3rd brake light, rear glass defroster etc.) are good.
Therefore, there is less incentive for me to peel back and look lol...
- The only thing that does not work is the rear wiper motor.
- Plugged a brand-new Volvo wiper motor to the connector just to test: nothing no activation of the new wiper motor with the wiper stalk activated.
- Wiper Relay: good. Removed relay, added a jumper wire in larger-blade terminals (jumper with fuse for protection, you can buy it at local auto parts store), there is 12V at YELLOW connector near the Wiper Motor.
- Switched to Ohmmeter mode, with relay out, checked YELLOW pin on connector and the UPPER terminal of the socket: 0 Ohm ---> so the YELLOW wire is intact.

The Wiper motor has 3 wires:
- Black (ground) is good.
NOTE: the bolt on the REM is NOT a ground source. For a good ground source, use the middle pin
of one of the black relays (see photo).
- Yellow wire has continuity to the upper relay pin in the REM (yellow wire not broken).
- Key position II, and rear wiper activated at the wiper stalk area. Checked the connector (disconnect
connector first) at the wiper motor:
* Black + Yellow: 12V
* Black + White: 0V (supposed to be 12V???)

Looks like the rear wiper motor has proper 12V supply via Black and Yellow, but somehow White wire does not
have power going to it. So possibilities are:
1. Bad White wire (why only 1 wire is bad in the wiring loom?)
2. Bad REM but only the white wire part!
3. Wiper stalk?
4. Bad CEM? But only rear wiper motor portion?

My future project when I have time:
1. Get a used wiring loom from junk yard and use it for the purpose of testing the 3 wires feeding the rear
wiper motor.
2. Get a used wiper stalk for testing.

For now, a dead rear wiper motor is not a big issue, I am living with it for now.
But I am curious how others troubleshoot the issue.
I think the mystery is in the White wire, which controls the function (full on vs intermittent).

If anyone smart enough to figure out this REAR wiper motor, please share your tricks/photos, I'd appreciate it...

- Anyway photo showing the flow of electrical signal (RED arrow showing electrical flow):
Wiper Stalk ---> CEM ---> REM as shown (previous photo by @abscate) and this photo:

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V70-Rear-Wiper-REM.jpg (92.46 KiB) Viewed 874 times

V70-Rear-Wiper-Circuit.jpg (90.47 KiB) Viewed 850 times

[abscate]

Thank you all for posting the electrical diagram for REAR wiper motor, but that is for 2005-2007 V70.
For 2001-2004 model, I played around with it during the weekend...

Ugh. CANBUS changed ftom 2004vto 2005 of course

[br0dy519]

One of the best things I did to my wife's XC70 was remove the rear wiper motor, relay, and pump fuse, and put a glass bung in there from eBay. Total cost $20 and the heaters do a fine job of cleaning the rear window in the winter. Just had to give my measurement of the hole to this vendor on eBay, and he sent me three bungs all very close in size to the one I needed. He even included a little bottle of the sealant. Couldn't have been easier, and to be honest the rear window looks a lot better without the arm there.

https://www.ebay.ca/str/dewiperltd

[cn90]

I no longer have access to the 2004 V70 (kid in college and I am home)....

From my reading elsewhere, Black + Yellow supplies ground and 12V, resptively.
These terminals are on standby, waiting for "command", which comes from the White wire.

The analogy is a Bosch relay, 30 and 87 are on standby and the command comes from 85-86 terminals.

Anyway, I suspect the White wire is not sending the signal to the Rear wiper motor, and the Relay
for the white wire is hidden further forward on the REM, necessitating removal of the bigger panel to
get to it for testing.

Anyway, if anyone does testing on the Relay for the white wire, please post bc I don't have access to
the car until the summer of 2023...

[CaptainThrifty]

2004 XC70, got my 2004 XC70 back from the body shop for a dent in the hood, everything looked good but the rear wiper wouldn't go. I found this post, pulled the fuse from the rear electronic module for 15 minutes, and VOILA! Wiper functions again. Thanks to all and sundry, I know if I had taken it back to the shop and complained they would have (A) denied involvement and (B) kept the car for a week and charged me 300 dollars to find the issue.

[abscate]

It sounds like theCANBUS driver went on strike for full dental. The reset put him back to work.

[jonesg]

Yes there is a relay. I had this same problem on my 2001 V70 T5. If you can find the Volvo V70 electrical pdf, I can direct you to the relay. Unfortunately, I have a hardcopy but not the pdf. The relay can be found on page 138, diagram 2/72. From the top of the relay panel, it's the 2nd to the left (square box). As I recall, I had to remove the plastic molding on the side of the cargo panel to access that particular relay. The relay is similar to other relays, so you could just do a swap and see if it fixes your problem. I ended up going to the junk yard for some cheap spares, and it's functioned fine ever since I changed it out. Now that I recall, it took me forever to track the non-functioning rear wiper to the relay. Best of luck, but I'll bet that is your issue.

do a reverse trace, disconnect battery, put the signal on the power feed at the wiper motor and trace it back with a fox/hound circuit tracer.
I used it to trace unknown wire on my snowmobile, took 30 seconds to find out what it was.