S40 (New) Electrics : Guide: Replacing the boot wiring harness

[Snoodini]

Hi,

I just replaced the wiring harness and lock mechanism on my MY2011 S40. It would seem that it is a common fault with this car that the wiring harness begins to break around the articulation point of the boot lid. Theres already at least one other guide on the swespeed on how to do this but I thought I would do an updated guide with more pictures. I hope people will find this useful.

This may be required if your car has any of the following symptoms:

• Boot Lid open message that won't go away despite it being firmly locked
• Boot Lid not opening despite fuse being OK
• License plate lights not functioning despite OK fuse and bulbs

Parts Needed

• Replacement Boot wiring harness: 8697604. I bought mine through a friend who is the internal parts purchaser for a local volvo dealership and service chain. It cost me 369 Swedish Crowns (£32 at the exchange rate at the time of writing)

Tools Needed

• Large Flat Screwdriver
• Pliers
• Small flat Screwdriver
• T25 (or if you're careful T20) Torx driver
• 10mm Socket or spanner (only needed if your boot won't open)

Time Required
Under 1 hour

If your boot will not open
If your boot will not open then it will take you longer and you will have a rather more tricky task ahead of you as you will need to do some of the steps plus a little extra from inside the boot. The steps to do this are a little different from the steps provided here, notably, step 1 can not be done as it requires that the boot is open. In your case you must remove the panel and let it flop down so that you can access the three 10mm bolts which attach the lock to the boot lid. you will also need to unplug the cable from it to be able to finally open the boot. To release the lock once you have it open you will need to connect your new wiring harness up (without routing the cable through the bodywork). I didn't need to do it this way so I have no pictures of it.

Alternatively, save all that bother if you have a North American sold model by just pulling the emmergengy release to open it...

The Procedure

1. Firstly you need to release the plastic cover from the locking mechanism. There are two clips which hold this on to the body of the lock mechanism, one is circled in red (the other is on the other side in the same position). to release the clips just slide your screwdriver in from the side and lever the clip away from the lock body. The cover now slides away.




2. Remove the hand grip. It is held to the body work by clips. Two on the wider side and one on the narrower side. Insert your screwdriver on the narrower side (the bottom edge) and apply firm but gentle pressure. At the same time pull the grip towards you and it should pop out. Be carefull not to push too hard on the clip as it is a single moulded piece and would need to be replaced if you break it.




3. You now need to remove the carpet trim from the boot lid. There are a number of plastic clips holding this in place and they can be popped off either by pulling with your finger nails or with a flat bladed screwdriver. If your car is fitted with a warning triangle holder as mine is then to remove this you just pull the pin out from the centre of each bracket, this pin releases the clips and they pull away very easily.



Pull the panel away from the boot past the lock and the two bumpers.



4. Disconnect the connector for the boot lock, you will need a small flat screwdriver to release the clip on the connector. The wiring is held in place with clips which are pushed through holes in the bodywork. remove these with pliers, some of them can be pretty stubborn, pull hard and don't worry about breaking them, they are only designed to be fitted once, the new wiring harness comes with clips installed.




5. Remove the boot handle by unscrewing the 4 torx screws (Circled in red) which secure it then disconnect the connector. There will be some resistance when you pull the handle piece away. There are a couple of clips which retain it however these are weak and there is no risk you will damage them by pulling it away





6. Disconnect the other end of the wiring harness (Circled red). the connection is in the top of the boot on the left hand side. it's easily accessible There are three more clips holding the wiring in place and a couple of them can be a bit of a b*#ch to remove.



7. Newer models of the S40 have an extra piece which holds the rubber conduit in place. if yours has this then you will need to remove it, by removing the two torx screws.




8. Remove the wiring harness. The rubber boots all just pull out of place from the body.

9. Install the new wiring harness by reversing everything that you just did. Take care to ensure the rubber boots are sitting correctly in the bodywork and that you do not twist the cabling. NOTE: I advise that you test the operation of it all before inserting the cable clips into the holes in the bodywork just to be sure everything is okay.

The replacement wiring harness I got seemed to be a touch more generous with cable length than the one I removed:



Here you can see the damage to the old wiring harness. the break was just inside the rubber conduit. one of the wires was completely severed with a couple of others on their way.

[Welton]

Fantastic guide, well done, I'm sure this will be a valuable thread for the future.

And look at the colour of that Sky, beautiful!

[VenomS40]

Super guide mate, we need more of these like this one on here! I've subscribed for future reference

[Snoodini]

Thanks for the positive responses guys!

I always like to research and plan how i'm going to do something before i do it so tha there's no suprises when i'm doing it.... i figure there's others like me so like to know what they're facing.

[froggyted]

Excellent guide. :-)

[chriscs40]

This is fantastic, thanks for posting, I am due to replace my Wiring harness this week, I'm just waiting for the part to arrive at the main dealers. However I just noticed that both of my 12V sockets aren't working either - would these be linked to the faulty boot wiring harness, or not?

[RCH2008S40]

Thanks for the excellent pictures and step by step guide. I've got the same problem too with my 2008 S40 2.4i sedan...started out with an intermitent trunk (boot) light, now my trunk automatically unlatches when I start the car and the license plate lights are now out. All associated with numerous wires breaking in the trunk harness.

Looks like I can't ignore it much longer...thanks for the information!

[Wooders]

Originally Posted by RCH2008S40

Thanks for the excellent pictures and step by step guide. I've got the same problem too with my 2008 S40 2.4i sedan...started out with an intermitent trunk (boot) light, now my trunk automatically unlatches when I start the car and the license plate lights are now out. All associated with numerous wires breaking in the trunk harness.

Looks like I can't ignore it much longer...thanks for the information!

Get it before it gets to the point where the boot doesn't open,turns into one he'll of a job then!

[RCH2008S40]

Thanks Wooders! The US version of the Volvo S40 has the interior emergency boot release pull handle. Good thing too...my wiring has deteriorated to the point where the boot won't open using the exterior boot release handle and the infamous "Trunk Open" error on the dash display.

I've got the new wiring harness sitting in the kitchen...will install it this weekend!

[nfosterma]

Earlier this summer, I had this same issue on my '09 S80, and I ended up brining it to the dealership for repair. However, this trunk release problem has now occurred on our '11 S40, so I ordered the part based on this post, and I will be making the replacement once it arrives. One question - does anyone know which fuse controls the trunk release? This was something that needed to be replaced as part of the repair on my S80, so I anticipate the same for the S40. Unfortunately, I can't find the fuse number for the trunk release within the owners manual for our S40. Any assistance would be greatly appreciated.