S40 V40: CEM Wiring/Repair Information

[bimmer49]

Florin78: It is explained in the VOLVO car manual book how to switch on and off the automatic lights.
When I imported my car into Spain I turned mine off too but there is no legal need to, it will still pass ITV.

[Commander]

Hi All, I am a very new member of the forum and would like to thank you all especially Gatos and jordanfc for all the info on this subject, spent two days reading up and printing off the wiring diagram started working on the car yesterday 27/02/15, at 10 am, soldered in two relays, all fixed by 16.30.
I have detailed the wiring diagram for high and low beams with the colour code but being a new member don't know how to put it on the site, To save time I also ran a wire from the Red lead connecting to the bulb (Disconnected from the bulb) outside the vehicle to the Drivers Footwell of the car and connected that to one of the probes on my multi meter and placed the other to the corresponding coloured wire to each of the headlight wires, that gave me a beep on my meter which told me that there was no break in the wire to that Headlight, also the same to the other side.
I also checked for voltage input to the CEM by removing the centre connecter of the CEM tracing the necessary wire (Yellow / Red and Yellow White) which confirmed that I had voltage into the CEM, that in turn confirmed all of your theory, Once again thanks to all, you save me a fortune

[baldmosher]

Originally Posted by Commander

I have detailed the wiring diagram for high and low beams with the colour code but being a new member don't know how to put it on the site

1. "Go Advanced"

2a. click the paperclip icon, a new popup/window will open
2b. click Choose File
2c. select your file (must be quite small so you might have to shrink it down in Paint first)
2d. click Upload
2e. check it's worked then close that popup/window

3. click Submit Reply

[andybeals]

Those of you with left-hand drive models will find the CEM tucked on the far left of the cabin, facing you. Remove the four screws holding the trim panel under the steering wheel and it will be right there, staring you in the face. All four of the connectors have a release tab that is conveniently mounted at the middle of the rear of the connector.

I replaced my left and right low beam relays early yesterday evening and now I no longer have a reluctant left-hand low beam that only comes on sometimes.

Thanks again for the info!

[The Robman]

Reviving this old thread to say that we just bought a 2000 Volvo S40 and one of the headlights was intermittent, but thanks to the info in this thread, I replaced the relay in the CEM and now all is good.

I bought the relay on ebay for $8 with free shipping, where the part was labelled "NEW Automotive Relays 15A 12VDC SPDT HI-CAP SEALED PCB"
http://www.ebay.com/itm/151741233627

[happy diver]

Hey, thank you well done.

How's the wind doing

[bobbytodd]

Originally Posted by bigboz

Just had a similar problem, main beams wouldn't come on, traced back to a dead power supply into the cem, relay and cem were fine but no input = no output

exactly my problem but it affected the fogs aswell

[OlaRullar]

I just replaced the (light) relays in the CEM, enclosed is a picture of what they look like.

Inside the plastic box there is another relay, which is inside some kind of a "shock absorber" or whatever...

The third picture is the connectors which apparently can fail. This one was not that bad....

[OlaRullar]

Does anyone know the value of resistor R142 in the CEM box? (It is on the back side of the circuit board). Today was not my lucky day, so I completely crashed it, it is no more... Nothing left of it....

[kieran40]

I thought for one horrible moment my cme relay had packed up luckily with a bit of advice from gatos and a new 15 amp fuse all sorted headlight working, thank god I haven't got all the agg