V70 Tailgate Wire Harness Repair

[abscate]

Fuse panel in the pillar. I dont think there is a plug in the roof

[cliffordhubbard]

any hints on how to remove panels to access fuse panel?
thanks
Cliff

[abscate]

Ive only done this on my 1999, and the P2 is different. On the left side, I think the trim plate just pulls down to reveal the fuse box - I had a thread on this when I got a bad fuse that knocked out my taillights

Up higher, Im sure you have to remove fasteners.

[chrism]

In the P2's, at least my 2003, the fuses and relays are all housed with at the CEM which is accessed by removing the left side panel (carpeted) between the wheel house and the left aft corner of the cargo compartment.

The tailgate harness disconnect is located in the LH "D" pillar. You have to remove the speaker grill and the speaker itself in order to pull the "D" pillar trim panel loose. As I recall there was also a tie wrap holding the tailgate harness in place near the disconnect so I had to cut it loose in order to free up the harness.

I believe I also had to pop the trim loose that runs across the top of the tailgate - at least the LH half of it.

[cn90]

Has anyone tried to replace 8645057, about $70-$80 for the new part from dealer?
This is the wiring loom for the tailgate...

[chrism]

A complete replacement of that harness would be the way the dealer would repair it, I’m sure. Probably most repair shops also. Time is big money in those situations so searching for the open or shorted wires could get costly. And from what I recall when chasing down the problem on mine, a complete replacement wouldn’t be too difficult. But on an older wagon it’s hard to justify spending 70-80 if it can be repaired for $1.50 worth of solder and shrink sleeve. Plus it would be less work to do the solder repair.

You see how badly mine was severed in the photo at the top of this discussion. That was about 10 years ago and the repaired wires are still functioning properly.

How bad is your damage?

[cn90]

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 are good (license bulbs, tailgate latch, 3rd brake light, rear glass defroster etc.).
- 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.
- Wiper Relay: good.

The Wiper motor has 3 wires:
- Black (ground) is good.
- Yellow has continuity to the relay pins in the REM (yellow wire not broken).
- Key position II, and rear wiper activated.
* Black + Yellow: 12V
* Black + White: 0V (supposed to be 12V???)

Looks like the rear wiper motor has proper 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.

[chrism]

If only one wire (white in your case) is in question, how about checking its continuity between its termination point in the door and where it arrives at the REM. That would tell you if you even NEED to consider tearing into the harness around the door hinge.

[firstv70volvo]

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 are good (license bulbs, tailgate latch, 3rd brake light, rear glass defroster etc.).
- 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.
- Wiper Relay: good.

The Wiper motor has 3 wires:
- Black (ground) is good.
- Yellow has continuity to the relay pins in the REM (yellow wire not broken).
- Key position II, and rear wiper activated.
* Black + Yellow: 12V
* Black + White: 0V (supposed to be 12V???)

Looks like the rear wiper motor has proper 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.

Yellow 12V to wiper motor is constant rear wiper motor on, white is intermittent wiper on/off. If you have 12V from the yellow wire to rear wiper motor and a good ground the wiper motor should run. White 12V may be intermittent on/off since it's the intermittent setting on the wiper stalk. Not sure how could possibly have a dead rear wiper motor if you have 12V and a good ground unless the motor is bad. If you have a known good wiper motor and 12V and a good ground measured at the motor there's no reason it shouldn't run.

[cn90]

Thanks for the info re WHITE and YELLOW wires feeding the rear wiper motor.
I have a brand-new Volvo wiper motor (in the blue box), plug it in and it does not run when activated.
Something weird is going on, I will continue to learn...

PS: This car is with kid in college, so I only "see" it a few days a year. Usually I focus on the important maintenance stuff and leave some stuff like this for another year lol...
But being curious, I want to learn exactly how this wiper motor works...

Attached is the REAR Wiper Circuit for 2001-2004 V70. I labeled BLUE for the relevant items...

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V70-Rear-Wiper-Circuit.jpg (90.47 KiB) Viewed 851 times