Haunted...by an electrical gremlin

[steveyorks]

I posted a week or two ago that Id swapped my S60 for a 2005 V70 D5 and was very chuffed. But not so much at the moment! I've noticed a few issues cropping up...all electrical such as the central locking being intermittent, when locking up the rear lights remain on or sometimes the interior light doesn't work. Tonight the rear lights stayed on when I locked it, as did the interior light and when I returned a minute later the front doors unlocked but the rear doors didn't. I tried the locking button inside to no avail. Even using the interior handle wouldn't unlock them. I drove it but the red light (alarm light?) on the dash top remained flashing as though the alarm was n't de-activated. When I got back home it wouldn't lock but the fob did make the interior light go on or off as I tried to unlock or lock. Its driving me mad.Despite all this it drives fine however its behaving. Obviously I will contact the garage I bought it from but does any of this sound familiar?

[steveyorks]

I also forgot to mention the rear wiper only works when it feels like as does the green light for rain sensitive wipers on the same stalk.

[Harvey]

These problems are sounding like the network is not happy.
You need to get the codes looked at before you start getting the wallet out.
Just too many faults.

[mikealder]

First thing I would check is the wiring where it runs through the left side tailgate hinge, the wires often break here and short out which can lead to fun and games when more than one circuit gets connected to another through broken wires, left too long such a fault can burn out the wiring between the REM and the tail gate, last one I looked at with this fault took two days to sort out the mess! - Mike

[Harvey]

This was my cable going into the tail gate.







But the fault I had was rear doors not locking or tail gate.the front doors were fine.

[mikealder]

If the wiring to the tailgate breaks then the items connected to that wire stop functioning, if more than one wire breaks and they short together you can get really strange faults from the car such as tail lights staying on because the wire to the number plate lights has shorted to the tailgate open switch for example - Mike

[steveyorks]

That sounds quite likely when you add all the faults up.The intermittent functioning of the rear wiper alone suggests a break in the wire. I did replace a rear number plate light at some stage and I'm wondering if that may have disturbed something as well. Is it easy to access the wires?

[mikealder]

The wiring isn't difficult to check, remove the plastic cover over the cables on the left hinge point then cut off the heat shrink/ fabric sleeve surrounding the cables, take care not to cut any cables, once you expose the wires have a good look at them for damage, easy to repair using a soldering iron and some heat shrink to cover the soldered joint, replace one wire at a time across the hinge point with new wire, only do one wire at a time as there are more than one wire per colour used - Mike

[steveyorks]

That's brilliant thanks I ll have a look when its light. I really appreciate you taking the trouble to reply.

[steveyorks]

Managed to get home a little early to have a quick look. Peeling back the covering heading from the hinge down towards the roof I found two wires where the core was exposed. Light was fading so I have taped over them for now as they were not broken. So far so good. On first starting the car the red alarm light was still flashing on the top of the dash but turned off and on again and this time no flashing. Central locking button on the drivers door is still not working though so I may have missed something. Its hard to tell if I have actually addressed the problem as it was an intermittent thing but time will tell. I ll have a better look over the weekend.

[M-R-P]

It might be worth removing the roof trim (screw under rear interior light) and the n/s D-pillar trim and inspecting the rest of the wiring, there may be other breaks in the cable. The last one I fixed looked fine from the outside, it wasn't till I got under the trims that I found a load of exposed wire.

[steveyorks]

Yes I think you are right. I can also go a bit further down the wire given a bit more time but I thought it unlikely breaks would be further down where the wire isn't flexed. The rear wiper and central lock button are not working and nor is the green light/button on the wiper stalk for the rain sensing wipers so its still not sorted, though this may be nothing to do with these wires.

[mikealder]

Depending upon what has shorted out it could have burnt the insulation off more wires within the car where the harness runs down the D pillar then around the far left corner of the car in the boot back to the REM, the last one I looked at had done this and damaged even more wiring in the main harness - Mike

[steveyorks]

Cheers Mike, I'll get an idea whats not working this week and then try and get it stripped down this weekend. Thanks for your help.

[mikealder]

One T20 head bolt to remove in the trim on the left near the edge of the head liner, then take the trim out including the speaker in the left D pillar, strip it out so you can inspect the wiring, also on the tailgate pull the upper trim off that surrounds the rear window, this lets you get at all the wiring involved.
If you do start to solder new wires in to replace the damaged section, only do one wire at a time as there are more than one yellow coloured cable and a few black ones making it easy to muddle things up if you chop out the whole lot in one go, over the top of the soldered joints shrink a length of heat shrink down to cover and protect the joint, I usually chop out about 12" of cable to ensure I get all the damaged section out and do all the wires, if one or two have failed the others will have been subjected to the same amount of flexing so they won't be far behind failing either.

As for the rest of the wiring in the rear of the car have a good look at it for burnt insulation, if you find any repair them by soldering in new lengths of cable again one at a time - Mike

[steveyorks]

cheers Mike. You don't know what colour wire is for the rear wiper and the central locking do you?

[LeeT5]

Managed to get home a little early to have a quick look. Peeling back the covering heading from the hinge down towards the roof I found two wires where the core was exposed. Light was fading so I have taped over them for now as they were not broken. So far so good. On first starting the car the red alarm light was still flashing on the top of the dash but turned off and on again and this time no flashing. Central locking button on the drivers door is still not working though so I may have missed something. Its hard to tell if I have actually addressed the problem as it was an intermittent thing but time will tell. I ll have a better look over the weekend.

This is normally because of a failed or failing drivers door lock motor.

However, I agree with Harvey on this one. It's all well and good pulling wiring harnesses apart and hoping to find a bare or broken wire but you've already told us that your boot lock works fine and there's no fault with anything in the tailgate.

Have you read your fault codes? Can you list them all here?

[Harvey]

The tail gate harness has three plugs on the rear fuse box,you could just unplug one at a time to see if things change.

This is the earth wires plug


This plug is the power plug to the heated rear window.


This plug does the number plate lights,central locking,wiper motor.


Well this is what my V70 has I don't know if all years are the same ?.

[steveyorks]

I have found a couple of bare wires in the rear wiring which I've insulated today so am still waiting to see what change if any, that that might make. Rear wiper only works when it feels like and from what you say central door locking button may be an unconnected issue though it did work last week. I've not had chance to get codes read yet (I don't have a reader) but was trying to eliminate what I can before shelling out any cash.

[steveyorks]

Just to update you all and thanks again for the advice. I have stripped the insulation back into the roof and down into the tailgate and only found the damaged wires I had already found. These I have now repaired properly. I had a good poke around in the fusebox, checked all connections etc and then re assembled trim, headlining etc. So many fiddly clips and interlocking bits of plastic I am surprised it doesn't creak more. Anyway upshot of it all is that so far so good so fingers crossed. I dare say I wont be sure for a couple of weeks as it was an intermittent fault but we will see.