Lost supply to 12v cabin sockets

[YorkshireDave]

An odd one!

Registered in 2006 I've checked every fuse on the CEM and in the engine bay. Manual says fuse 11 on the CEM but its fine. Checked there is 12v to the fuse itself. From there nothing at the AC socket, nothing at the middle socket. Checked all the connectors I could find too.

It 'was' working fine so something's amiss. Any suggestions peeps? No I'm not selling up cos, cos. cos

[SwissXC90]

There's not much to it

A 2006 XC90 has the wiring like this (taken straight from the wiring diagram)

Fuse F11 on the CEM feeds power to pin A17, and from that pin a violet wire goes to device 9/1 (Outlet 12V front) and then onwards, as a violet wire, to device 9/25 (Outlet 12V rear)

Both come from the same 12V power source
Both are grounded at grounding point 31/10 (A-pillar, right-hand side)

Make sure you do not have a ground issue by measuring the power using a multimeter, and with the multimeter negative connected to various other ground points.

If still no power:
Remove and inspect the CEM.
The power is switched by a relay built into / on the CEM, you may have a fault relay / burnt contact / water damage through corrosion

If the CEM is an early version, the relays are plugged in and can be easily replaces.
if a later version, the relays are soldered to the circuit board, and can still be replaced, solder skills required. Or you can jury-rig an external relay to do the same function as the failed relay.

[YorkshireDave]

[QUOTE=SwissXC90;2771772]
Deleted the dup post

[YorkshireDave]

Originally Posted by SwissXC90

There's not much to it

A 2006 XC90 has the wiring like this (taken straight from the wiring diagram)

Fuse F11 on the CEM feeds power to pin A17, and from that pin a violet wire goes to device 9/1 (Outlet 12V front) and then onwards, as a violet wire, to device 9/25 (Outlet 12V rear)

Both come from the same 12V power source
Both are grounded at grounding point 31/10 (A-pillar, right-hand side)

Make sure you do not have a ground issue by measuring the power using a multimeter, and with the multimeter negative connected to various other ground points.

If still no power:
Remove and inspect the CEM.
The power is switched by a relay built into / on the CEM, you may have a fault relay / burnt contact / water damage through corrosion

If the CEM is an early version, the relays are plugged in and can be easily replaces.
if a later version, the relays are soldered to the circuit board, and can still be replaced, solder skills required. Or you can jury-rig an external relay to do the same function as the failed relay.

Thank you! Proper insight

Interestingly the Haynes manual says it's fed via another fuse which it calls the battery fuse box! I've pulled & checked every fuse I could find including the battery distribution block ones to no avail...

As part of my recent painful experience diagnosing a defective DEM, I had the joy of removing the CEM. Due to the symptoms displayed (or not), I was flabbergasted to find not a single sign of corrosion or water damage anywhere that I could see on the CEM. As there was copious amounts of silicone 'gobbed' around it I suspect it has been changed from the original. From (poor) memory I got the impression it was a later version.

I'm as happy as a 'pig in...' to replace components, however, daft as this may sound, how do you get into the darned circuit boards? I got the impression it was like a bl00dy Rubik's cube and the last thing I wanted to do is damage it!

Any idea on the model of relay? If can know I'll pre-order from RS or Farnells. I do have some small 12v ones knocking around, hopefully they'll take 30A if I parallel up the contacts, so if you don't have the info I can always jury rig. I'd be a little concerned about the coil current and of course would need a suitable diode across.

My biggest issue is that I need the vehicle every day so it can only be off the road for a short time. Can't wait to retire

[SwissXC90]

Google "replacing relay CEM" ... and voila:
https://www.volvoforums.org.uk/showthread.php?t=217111

BUT confirm first. Look for 12V on CEM pin A17. Only start to take the CEM to pieces if you have confirmed pin A17 has no 12V.

[YorkshireDave]

Originally Posted by SwissXC90

Google "replacing relay CEM" ... and voila:
https://www.volvoforums.org.uk/showthread.php?t=217111

BUT confirm first. Look for 12V on CEM pin A17. Only start to take the CEM to pieces if you have confirmed pin A17 has no 12V.

CEM pin A17?? Please enlighten me!
BTW the Panasonic relays are now obsolete! Yet another bl00dy challenge

[SwissXC90]

Originally Posted by YorkshireDave

CEM pin A17?? Please enlighten me!

I've now mentioned CEM pin A17 twice.

What more is there to say?

[Harley Dave]

Original deleted
Cheers
Dave

[Harley Dave]

I think we may be looking at/for the wrong "fuse 11"

Look here

http://www.volvohowto.com/volvo-xc90...-and-amperage/

You need the fuse board that's under the steering column.

Cheers

Dave

[YorkshireDave]

Originally Posted by Harley Dave

I think we may be looking at/for the wrong "fuse 11"

Look here

http://www.volvohowto.com/volvo-xc90...-and-amperage/

You need the fuse board that's under the steering column.

Cheers

Dave

Thanks Dave. I'm def checking the correct one thanks. It's the one on the CEM under the steering wheel.

Swiss. Is there some kind of header with pins accessible then? Any idea if there's an image I can ref? Perhaps in Vida? Is it a plug reference? I have no idea!