Help please, Brainiacs! Weird Central Locking problem...

[Al115]

Car is a 2005 V70R - that KNOWS that tomorrow is the one day in the month when I really need it to work! :)

Symptom is that the front doors will lock and unlock on the central locking (fob or cabin button), but the rears / tailgate / fuel filler will not. The 15A fuse 28 in the REM ("Central locking system") blows every time I lock the car.

Fuses etc here: http://new.volvocars.com/ownersdocs/2005/2005_v70/05v70_08a.htm#pg130
I have the wiring diagram also.

I suspect that possible culprits might be one of the three (rear door & tailgate) door lock motors, or some chafed wiring, or the deadlock relays in the rear doors. Not the fuel filler cap solenoid as that doesn't fire up until 10 mins after the car is locked.

Any suggestions on what to try next? I really don't want to take the door panels off if I don't have to, as the plastic clips are really tight and I know I'll damage something. But I can't see a way to isolate the door locks (so I can test for left/right fault) without doing that.

I'll go out and disconnect the tailgate lock next, while I'm having a think. All suggestions welcomed!

[Al115]

Interesting development (at least, interesting to me): when the tailgate is open, the lock actuator moves, but the fuse doesn't blow. Shut the tailgate and the fuse does blow.

Making progress :)

[Al115]

So... I have a workaround - lock the car with the tailgate open - then close the tailgate - all is locked and the fuse is intact. Unlocking doesn't blow the fuse.

At least I can use the car (even if I have to travel around with a pocket full of 15A fuses...)

Now to solve the problem!

[LeeT5]

Al.

removing the door cards is very easy on your car. You won't break anything unless your a buffoon!! Just take your time. There is a good how to on You tube for the P2.

Regards the rear tailgate, that easy too. You just need to be brutal pulling down the corners of the door card when the tailgate is open. Once its popped then continue along untill the card comes away. Don't forget the 4 Torqs 25 (i think) screws in the bottom and sides of the tailgate first!

From what you've said, it does sound like a chaffed wire in the tailgate. I can't remember where the lume is when i removed mine. Volvo wiring diagram will help.

[silverhorse]

unless your a buffoon!!

LOL, not heard that word for ages!

[M-R-P]

As you look at the back of the car, the loom runs through the left hand hinge. The loom tends not to fray in the tailgate, but in the roof void where the loom comes through.
Pry the boot light out of it's socket and undo the T25 bolt hiding under the light. Pull the plastic roof panel off and you'll be able to see the tailgate loom running down into the corner of the car. It connects to the main loom, just behind the reversing light. The most likely place to fray is at the back of the hinge, where it rubs on the metal.

[Al115]

Thanks guys.

a) it was the tailgate lock (not unlock) causing the fuse to blow
b) the solenoid was fine - it was the mechanism that had become misaligned inside the gate - so a cheap and easy fix!

I've already repaired that bit of wiring in the past, so I'm glad I didn't have to go back there again.