Wiring Harness not working

[Rodbr]

I followed instruction for the installation of the 13 pin harness and module. These were new but nothing seems to work. I fitted an adaptor from 13 to 7 pin and checked pass through before fitting so that is not the issue.
Any tips to check that I can go through would be most welcome.

I do not need the fog lamps, 12 volt power, or other extras included as possible with this harness.
Rgds
Rod

[Oldbrook]

Hi not 100% sure but maybe the car needs telling this is fitted via vida. Dave

[TruckbusUK]

A step for a hint as to which XC90 we are talking about and what age, I assume we are talking about the towbar electrics? The harness changed in 2005 so have you confirmed you have the correct one for you car?

[SwissXC90]

And help us by saying what does not work.... if everything, then look for common points of failure, which is really only the ground wire, or the loom is not plugged in...

[Rodbr]

2006 XC90 SE D5. Geartronic,
Nothing works: Does it cause any issue as I have only tried with an LED trailer board that I know works fine on the Jeep Cherokee.
As you say not much to screw up. Two plugs to TRM module and one to side fuse panel and two fuses and an earth.
These were bought new from the supplier in Wales that is recommended on this site.
Is there a way to check with using the TRM module to isolate the issue?
All searches say that a software upgrade is not necessary?
Rod

[SwissXC90]

Focus on one thing, like reverse lights.

The reverse lights on the trailer socket are in parallel with the reverse lights in the car's rear taillamps, and are fused by the same fuse. There's no fancy switching or anything.
(I know because I blew the reverse lamp fuse when a trailer I towed had a short on the reverse lamp.)

So the trailer socket reverse lamp gets power through the same reverse lamp fuse, and is grounded by the trailer wiring ground.
You do not need any software to activate the trailer wiring reverse lamps.

Test it with a voltmeter:
Do you get +12V on the reverse lamp pin when the car is in reverse and the vehicle's reverse lamps are on?

Using an ohmmeter, do you measure a ground on the ground pin of the trailer socket?

Or: use a spare 5W or 10W 12V bulb, and test the reverse light pin of the trailer socket to any vehicle ground, and then to the trailer socket ground.

You'll quickly see it it is working properly.

[TruckbusUK]

Originally Posted by Rodbr

2006 XC90 SE D5. Geartronic,
Nothing works: Does it cause any issue as I have only tried with an LED trailer board that I know works fine on the Jeep Cherokee.
As you say not much to screw up. Two plugs to TRM module and one to side fuse panel and two fuses and an earth.
These were bought new from the supplier in Wales that is recommended on this site.
Is there a way to check with using the TRM module to isolate the issue?
All searches say that a software upgrade is not necessary?
Rod

I'm guessing from this the parts are genuine Volvo and came from FRF Volvo, if so at least we should be able to assume that the parts are correct for your car.
Can we also assume the harness to the TCM and TCM to the control panel in the NHS rear wing are all connected, the supplied fuses are all inserted and the ground cable is connected.

If so I guess following SwissXC90's steps is the way fwd.

[Rodbr]

Tried every combination to get the plug working and can not get any feeds at all.
Is it likely that a software update might do the trick?
Can someone please send me the details of the Volvo parts supplier often recco'd by members in Wales?
Rgds
Rod

[Harley Dave]

If you can tell us exactly, step by step, what plugs you have connected to what we can possibly see where something has gone wrong

For instance IIRC there's an earth wire that is connected near the battery.

Have you connected that?

I note you didn't want the additional functions, but did you insert the 4x new fuses into the fuseboard?

Cheers

Dave

[TruckbusUK]

Originally Posted by Rodbr

Tried every combination to get the plug working and can not get any feeds at all.
Is it likely that a software update might do the trick?
Can someone please send me the details of the Volvo parts supplier often recco'd by members in Wales?
Rgds
Rod

As per my previous post, did you confirm if they were genuine Volvo components you had used, and the correct ones for your car? .... this post suggests maybe they were not, I think we need to establish exactly what parts you are using?