I have a 2006 V70 and the only problem right now is the rear door won't lock/unlock. Drivers door opens with one click of the remote and the front and back doors open with a second click of the remote (that's how its setup). Passenger cabin doors lock by remote. However, the tailgate doesn't lock or unlock by the remote.

The alarm is set off when the rear door is opened (despite it not being locked) and the interior lights come on when the rear door is opened

I've searched here and find a few possible causes but want to start with the basics - fuses and relays. I've been looking for the door lock relays and can't find them. The wiring diagrams I've found as well as relay location guides on the internet show them in the rear drivers side fuse box but in my car there seem to only be fuses in that location. The relays in the engine bay don't seem to be related. Also some internet searching seems to indicate the wiring and relays/location differ somewhat by year?

So, assuming that relays are a thing to check as a basic troubleshooting, where are they located in my car?! I've checked all the fuses I can find in engine bay and rear drivers side. Once relays and fuses are ruled out, I'm guessing tailgate wiring and the lock latch mechanism itself would be the next steps?

Better yet, any other suggestions on what the problem might be? I do have VIDA but haven't tried that yet.

Been distracted by life and just now getting back to this.

I tested the wires for continuity from the rear module thru the flexible hatch wiring to the plugs that goes into the latch mechanism. All were fine so that eliminates problems in the hatch wiring. Also the wires as the exit/enter the hatch look in good condition.

Upon plugging the connector to the latch mechanism back in I messed with the door remote again and did in fact get some noise from the rear hatch. I then decided to lock/unlock the door using the remote. It seemed to lock and then when i tried to unlock I could see some smoke (thru the rear window) coming from the latch mechanism area and it did not unlock. I then couldn't unlock the door at all! Luckily, I had all the trim off so crawled in the back and manually pushed the unlatch lever. It now looks like the pushrod is not contacting the latch lever. I suspect the motor may have somehow overextended resulting in the lever no longer contacting the lever and frying the latch motor (hence the smoke!) at the same time

So this all seems to point to it being the latch mechanism that is the problem and needs to be replaced.

So next problem - I'm struggling to remove the latch mechanism! I have removed the three screws that hold the latch mechanism on but can't figure out how to remove the mechanism since the actuator rod goes thru its frame. I've tried to loosen the actuator rod pivot mount (there is one screw) to provide more wiggle room so the latch mechanism can be wiggledout but the pivot mount has some form of blind fastener in addition to the bolt which I can't seem to figure out how to release. Any suggestions?

I'm going to buy a secondhand latch on eBay (unless there are suggestions of a better source) but will need to remove the latch to install it!

Just to close the loop on this one. I managed to figure out how to pop out the actuator wire to allow removal of the latch unit. Upon bench testing it confirmed that the electrical actuator was bad. One used unit from ebay later and everything works again. Care is needed because latch units, even for the same year, seem to vary from car to car (based on options?). Mine (a 2005) had a metal spring around the actuator wire which earlier (00-04) and some of the same year didn't seem to have. Match the pictures of the actual replacement part carefully if buying online..

This kind of electrical misbehavior sounds a lot like failed wiring within the LH tailgate hinge area. Here’s a pic of what mine looked like when I finally decided to dig into the harness to fix multiple problems:

Agree,

There's a cable tie installed too tight during the factory installation that can eventually bind and break the tailgate wires through years of flexing. Happened on our car too (2000 V70). (Didn't use another cable tie when reassembling).

Splicing and/or soldering the wires should correct the tailgate electrical issues.

Thanks Chris and Robert. Tailgate wiring is certainly on my list of possible causes. However before ripping apart the tailgate to get to wiring I wanted to check the relays (which I can't find!). Where should the relays be located in a 2006 V70 FWD? Nothing in engine bay, drivers dash or drivers rear fuse boxes that I have found.

My 2000 P1 V70 has a tailgate release adjacent to the fuel flap lever on the drivers door. If you have one, does that work. If not it reinforces the chance that it is the tailgate wiring shown.

Hi Derek,

I agree with you that Chris probably nailed the fault with the first post.
I just looked for his manual at Duckduckgo and quickly found the Volvo number
at a Google proxy site: TP3989202 $$$$$$$$$$$$
Then searched for "Volvo TP3989202", and blow me down, I got the manual.

Iam, are you getting this?

http://vidaresources.volvocars.biz/ewd/US%20Eng/3989202/index_3989202.html Bingo

Bill

Hi Iam,

What you want to find is the Volvo wiring diagram for your model year.
It has pictorials of what things look like and where they are located.
Schematics, all specific to your car.
All of the details you need to DIY troubleshoot wiring, your best pal.

Try the search engines for the PDF manuals on-line and look for hard copy manuals on Ebay, they are always popping up.

Good luck, Bill

Thanks Bill

Yes, I have several wiring diagrams which almost seem to vary by year although with regard to the central locking they are all essentially the same schematically. The diagrams aren't the problem. And I'm an expert googler (!) and have found multiple images of fuse/relay box locations which broadly align with my car but seem to err when it comes to the actual location of the tailgate relay in question. The problem I have is the actual physical locations which seem to vary by year and maybe even manufacturing location (?). I have found several references to the tailgate lock relay being in the rear drivers side fuse box area. The only challenge is that they are not there in my car. In fact I can't find any of the door lock relays. I think mine is a late year 2006 V70 so maybe they change the layout by then?

I may just pull our VIDA to see if that helps with schematics, locations and maybe even allow me to test lock activation and relays without actually knowing where they are physically!

Hi Iam,

Use your VIN number to get the right info. model year etc.
Start there.
I can help if you can't find a translation table.

Being an expert Googler isn't all you think it is with Google being a sleazy internet monopoly. Try other search engines.

Look for the list of Volvo service publications and get the number of your
wiring diagram, TP--- ?---

That's what you want, not something close.

Bill

By VIN would obviously be the best. What sites/sources do you recommend to get this information for my specific VIN?

I had some links that I used previously but those links now seem to be dead.

Now might be the time to pull the tailgate moulding panels and check integrity of the tailgate harness. If the wires are broken, it's likely that the relays or fuses aren't the problem.

I have the info in the Volvo pocket data book.

Looked it up at duckduckgo

and there's a pile of offerings:

here's one: https://volvoforums.com/forum/vindecoder.php

You could get it from any Volvo dealer

You could also call your Volvo service department and inquire about
the Greenbook wiring diagram / service manual
(after you give them the VIN nr)
They will likely say it's NLA.

Then you ask for the number and search for it on Ebay and on-line.

You'll find out how cooperative Google is when they send you to their proxy sites
wanting $$ for unknown data.

Cheers, Bill