S40 V40: CEM Wiring/Repair Information

[swordsmanvolvo]

Hello mr gatos
I have a 2001 s40 (with fogs) and am pretty sure it needs a new CEM to fix the headlight relay problem. I already checked the bulbs and fuses. There are some (CEMs) on ebay but I am reluctant to take a chance on these - I wonder to you have any more for sale which will work with the fogs?

[gatos]

Have you checked the voltage across the headlights? Do you get 12V?

Can you let me know what the part number on it is. You most probably have the 30621305. I can program/enable/disable different things and test the CEMs on my car to make sure everything works

[swordsmanvolvo]

Thank you for replying
No, read a few threads here and in various other places an formed the view it was the CEM.
I don't have the expertise or equipment to check the voltage
I was driving along one evening - lights working ok then switched to headlights and back low beams and they were gone
I will check the part number tomorrow evening
It seemed worth the few euro to chance replacing the CEM?

[gatos]

Originally Posted by swordsmanvolvo

Thank you for replying
No, read a few threads here and in various other places an formed the view it was the CEM.
I don't have the expertise or equipment to check the voltage
I was driving along one evening - lights working ok then switched to headlights and back low beams and they were gone
I will check the part number tomorrow evening
It seemed worth the few euro to chance replacing the CEM?

You will know it is a failed CEM, when you get a voltage reading with a meter, but the bulb is not working. It is an odd occurrence.

If however you don't get any voltage readings, then it could be something as simple as a fuse, or worse case scenario a sorting of the loom under the radiator.

Also it would be a good investment to get a cheap multimeter as they do come handy. And if you don't know how to use it, there are plenty of video guides on youtube.

£2.99 for a cheapy one http://www.ebay.co.uk/itm/DIGITAL-MU...item256cad5ea5

and there are many others at £5, £10 or £20.

[kirkwallcity]

This a really informative thread.

I bought an '03 V40 three weeks ago, but havenever got full beams to work. Not the fuses or the bulbs and both sides have failed. When I pull the lever to go to full beams I here a click which I thought was probably the relay (?) When the lights are set to sides or drls I can flash the full beams though which seems strange. Interestingly, the garage which serviced the vehicle for the previous owner says they have put in a new CEM.

Any thoughts?

Bob

[gatos]

Most probably they used an older CEM.
I think your car should come with the CEM with part number 30638708. If you look under your drivers footwell, you will find out that you most probably have either the 30621305 or 30896698 fitted on your car now

[kirkwallcity]

Hi Gatos,

I checked the part this morning and it does have number 30638708. Is there any possibility that it should be one of the others? Alternatively, is it possible that it's a relay? I hear the relay clicking away.

Cheers

Bob

[gatos]

These are the various part numbers for the CEM:

Control unit [-2001, L.H.D (30859699)] 30896697
Electronics box [2002-, L.H.D (30621304)] 30638707
Control unit [-2001, R.H.D (30859700)] 30896698
Electronics box [CH 800000-026445, R.H.D] 30621305
Electronics box [CH 026446-, R.H.D] 30638708

By checking your chassis number (last 6 digits on your VIN) you should be able to find out which CEM your car should have.

What part number is the CEM you have?

The relevant relays are actually inside the CEM

[Clan]

Originally Posted by gatos

These are the various part numbers for the CEM:

Control unit [-2001, L.H.D (30859699)] 30896697
Electronics box [2002-, L.H.D (30621304)] 30638707
Control unit [-2001, R.H.D (30859700)] 30896698
Electronics box [CH 800000-026445, R.H.D] 30621305
Electronics box [CH 026446-, R.H.D] 30638708

By checking your chassis number (last 6 digits on your VIN) you should be able to find out which CEM your car should have.

What part number is the CEM you have?

The relevant relays are actually inside the CEM

To confuse matters dont forget the chassis numbers went back to zero around 2002

[kirkwallcity]

9####5 is the last 6 digits ln the chassis/vin and the part number of the CEM is 30638708.
Thanks for all your assistance.
Bob