S40 V40: CEM Wiring/Repair Information

[mrbroons]

I have tried the test and my lights light up all the time, just seems to be whilst driving they cut out, does this point to a bulb or igniter failure?

[MiasMum]

Does anyone know if the CEM controls the sidelights? I have a 2000 V40 1.8 XS and none of the sidelights are working. Hubby says he has checked fuses and bulbs and says he can hear a relay clicking and is wondering if the CEM isnt sending power to any of the sidelights for some reason? (Headlights work if the switch is in position 0 and in headlights on position, both with engine on and off but no sidelights at all.)

[qipan]

Originally Posted by mrbroons

I have tried the test and my lights light up all the time, just seems to be whilst driving they cut out, does this point to a bulb or igniter failure?

So it is inconclusive. Do not think it is due to the bulb but I could be wrong.

Maybe you can try cleaning the electrcial contacts of the light by using some electronic cleaning solvent (not the mechanic type like WD40). I have used it to clean the door light switch to make it work again.

[Mikez]

Originally Posted by MiasMum

Does anyone know if the CEM controls the sidelights? I have a 2000 V40 1.8 XS and none of the sidelights are working. Hubby says he has checked fuses and bulbs and says he can hear a relay clicking and is wondering if the CEM isnt sending power to any of the sidelights for some reason? (Headlights work if the switch is in position 0 and in headlights on position, both with engine on and off but no sidelights at all.)

Are you sure the relay is working fine? I have a 2001 V40 1.8 which had a failed LH dipped beam. I knew the relay would be faulty when I read this topic, but it seemed to work when I tested it. I mean, there was around 12 V voltage when lights were turned on and zero voltage when lights were off. It looked like the relay would be OK (you could have heard a clicking sound if you had decent hearing), but still, there was no light. It somehow limited the current in such a way that it was not able to turn the light on. The relay may be faulty even if it seemed to be ok.

In my case, I fixed the lights by replacing the relay with about similar one.

[mmarreco]

Originally Posted by qipan

Thanks for the very useful information, Russell_S.

In my case, I have a V40 which had a failed LH dipped beam. The light was on if the engine was running and off if the engine stopped (all switches were on). Finally, this was traced to a problem with the relay on the CEM board. When the engine is on, the control voltage on the relay is about 13V, which is high enough to activate the old relay. When off, the battery voltage is about 11.5V, so the relay does not move at all.

The problem is definately with the relay. But to get a replacement relay is not easy. Dealers do not have the relay as a component but would charge about £450 for the whole CEM. In the end, I found a replacement from RS (stock number 217-2876) and only costs £1.47 plus VAT and del.

Link here:
http://uk.rs-online.com/web/search/s...7-2876&x=0&y=0

I have also attached the datasheet here. It is 15A compared with the old 20A, but well enough for the dipped beam (about 5A).

After replaced with the new relay, my V40 returns to normal.

Very useful info, thanks!

Was it easy to replace the relay on the circuit board? What tools did you use?

[pacman67]

Originally Posted by mrbroons

Hi, I have an XC90 (2003). My passenger side xenon dipped beam flicks on and off whilst I'm driving, sometimes it stays on for a whole journey other times it is on and off every 30 seconds, I've also got water coming into the cabin from somewhere (it's under the floor near the yaw sensor).

Just wondering if these things can all be linked. I'm really scratching my head with this one. I've posted under the proper forum section my problem but saw this thread whilst searching for an answer and just thought I would ask?

regards, Jim.

I have heard of this water problem from a local volvo specialist, if i remember the water comes in somehere round the handbrake cable, which in turn rusts and snaps. Seem to remember him saying he,d seen a few with a fair bit of water under the carpets. Hope this helps. If you need mor info pm me.

[qipan]

Originally Posted by mmarreco

Very useful info, thanks!

Was it easy to replace the relay on the circuit board? What tools did you use?

Was easy for me as I do soldering regularly. Maybe a bit tricky if no experience before.

Anyway I used a slightly bigger soldering iron tip (electronics tool) and some solder wick to absorb the solder as much as possible off the relay pins. And then gradually loose the pins inside pcb holes and gently pull the relay out while heat the pins at the same time. Once out of the board, it is easy enough to put a new one on. Good luck.

[V40DS]

Originally Posted by qipan

The problem is definately with the relay. But to get a replacement relay is not easy. Dealers do not have the relay as a component but would charge about £450 for the whole CEM. In the end, I found a replacement from RS (stock number 217-2876) and only costs £1.47 plus VAT and del.

Link here:
http://uk.rs-online.com/web/search/s...7-2876&x=0&y=0

I have also attached the datasheet here. It is 15A compared with the old 20A, but well enough for the dipped beam (about 5A).

After replaced with the new relay, my V40 returns to normal.

Hi, thought I would update this thread as the information posted above was a huge help providing me the information needed to repair my CEM. I have a V40DS on a '51 plate and the nearside dipped headlight beam would sometimes work and sometimes not, this had no real pattern whether ignition was on or off. I removed the CEM from the plastic enclosure and plugged it into the car as a bare board and when I found the headlight not on, flicking the corner of the board would force it on everytime. I ordered the above relays (£1.74 plus VAT + Shipping - 2 relays will actually cost you about £9.50 as the shipping is next day at £4.95). Desoldered the old relay and installed the new one and now the headlight is working perfectly.

Thanks again for the help and confirmation this procedure was correct for my circumstances as above.

Picture below shows new relay in the center, darker than the others.

[sebaveh]

Well, it happen to one of our fellow volvo owner, who happens to know about electronics too. He soldered new relay in place and it worked. Later, he went to analyse the old relay part. He took it apart. Guess what he found - inside was another, smaller relay, soldered to pins of outer shell. How amazing is that ?!?!

[Clan]

Originally Posted by Dog_Book

I wonder if this unit can be altered to turn off the DRL's :P

yes , just read your owner's handbook :-)