CEM Wiring/Repair Information
 

Hello everyone,
From Belgium, to thank you for the information published on the forum. Thanks to this information, I was able to repair the CEM by replacing one of the two dipped beam relays.
It works, the work is not very easy and requires patience.
But my 2004 V40 with 341,000km, can ride now at night .... Thanks Alan

Brilliant, well done. Future reference tho, if you replaced one, sometimes easier to swap both out with new ones. Unless it’s only me the second one fails within a week.

I changed both of mine, one had failed and the second one was bulging like the failed one, probably due to fail shortly afterwards. One year and no issues for me yet!

Cem
 

I greatly appreciate your post.
I purchased the Haynes book, and I am very disappointed, in the past I got a BMW Motorcycle book from Haynes, and that one is very detailed.
I knew there had to be some relays for the low beams, and by google I found there was a mention of a CEM....but I could not find the location in the car.
Your pictures above gave me hope...but again, I was confused as it shows right above the gas pedal...in my car is on the extreme left of the dashboard....I realized that you show the British car (I am in the U.S.)... I am happy I found this forum. I find that in the UK you care more for your vehicles. Thank you.

My second one failed a year later.

My dipped beam is out with a good bulb, I suspect the relay.

The P1CN012W1 is a very special animal. High inrush current rating (30A) low coil current (50mA 12V/233Ohm), small size 22x17x17mm, unusual 5 pin layout, Form C.

Tough to find a good substitute. Fujitsu is not making a direct substitute.
I'm thinking the whole design is a folly, judging by their recent offerings in automotive headlight relays.
Zettler AC943 has the same pin-out but less current rating. This may be OK if you can accept a shorter cycle life. If changing to LED headlight is an option then it would be OK. Same goes for the above suggestion.
Incandescent inrush current can be 10x the average current, may cause contact-erosion or -welding.

I'm thinking of remoting the relay(s) to a typical socketed automotive relay. Design wise, putting mechanical relays on a board is a bit "optimistic". Those harness contacts and PCB traces aren't very beefy.
The heat generated from those five relay coils is not going to help the reliability of the semiconductors on the board.

Hi all. This thread is extremely useful. Recently I had both dipped beams just fail on me, with all other lights working OK. I got hold of a used CEM with the same part number and fitted it; however, it isn't working properly. Dipped beams and side lights come on together when you turn the ignition, and on the internal light switch, when the side lights are on, the light indicator on the switch goes out, and when you turn the light switch off the indicator lights up...if that makes sense. Anyway, it would at least appear to confirm that it is indeed a CEM issues as the dipped headlights work!

In another thread, a helpful member said the "VIN" would be wrong even if I get a straight swap for a working CEM. In this thread though, swapping them out seems to be a generally accepted practice. My question is, is there actually any issue at all with swapping them for a CEM that is the same part number?

I have also seen people have unsoldered and soldered new relays for the dipped beam. This is tempting, but I haven't soldered since I was about 12 years old in the school electronics club 🤣 can someone confirm exactly what I will need for this - aside from a soldering iron and solder, please? Any specific iron, too?

Furthermore, does someone have a link for the exact relays that would work?

I have a 2003 V40 Sport 2.0 petrol engine.

The part number of the CEM in there at the minute, and that was working fine, until.recently, is 30621305.

Thank you for any help. It's much appreciated.

Which relay was it that needed fixing so that I can look it up in the company that you recommended for selling relays? Can you post picture too? I'm after relay for o/s/f indicator as mine has stopped working. Everything in lighting works just not o/s/f indicator.