S40 V40: CEM Wiring/Repair Information

[caprirob]

Hi guys

Just posted a wanted ad but hope someone can help

When I bought my car I noticed that a single wire had been taken from one headlamp to another - obviously taking some sort of feed.

The headlamps worked and as it has been so cold I havent got round to looking at it.

Anyway a road trip last night saw both dipped beams fail and had to drive home with the mains on

A bit of digging suggests the CEM is at fault, however as the aforementioned bodge has been done it has been suggested in another thread that this will have damaged the CEM beyond repair.

The CEM on my car is 30859700

It is a poverty spec 2000 V40 with single headlamps and no foglamps.

Can anyone tell me will another p/n CEM fit - I believe the S40 ones will work but have to be programmed to make the rear wiper work - is this hard to do ? mine does not seem to have a variable rear wipe - it swipes with the wash button or on the switch.

There are none currently on ebay matching my P/N - any help gratefully received - can't pm back yet as not enough posts so please post on this thread or my wanted thread

[caprirob]

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

So if mine has a 30859700 fitted now is the 30896698 a correct replacement ?

There is one currently on Ebay ( 30896698 ) but its described as being from an S40 so even if it will make the dipped beams work on my V40 the rear wiper wont ?

[caprirob]

This is getting right on my nerves

Managed to get 2 relays from Maplin yesterday unfortunately they are only rated 10A rather than 15A but a previous post on this thread indicated that should still be OK.

On removal of the CEM one of the relays was actually bulging so clearly something wrong with it.

Took me about 2 hours of fiddling to successfully de-solder and remove the old relays and then solder the new ones in.

Thought I had got a result when I plugged it all back in, ignition on, turned the lights on and went to the front of the car and saw them lit up

Unfortunately on turning off the switch and removal of the ignition key the headlamps stayed on !

So either the 10A relays arent up to the job and are permanently stuck on, or the CEM is knackered. Can anyone advise if the relays are too low amp-rated would this cause them to stick on regardless of whether the switch/ignition is on ? If so I can re-order the correct ones from RS - otherwise I Think I'm going to have to get to a breakers tomorrow and try and get a replacement.
I've been driving round all day with the headlamp circuit disconnected at the CEM - thankfully the brake lights and indicators seem to be controlled separately but I have no main beam with it unplugged and naturally can't drive it in the dark.

Does anyone within a sensible travelling distance of Cannock have a spare CEM I can try tomorrow ? 2000 Model V40 1.8 ( the date on the CEM I have is 10/99 )

[Clan]

Originally Posted by caprirob

This is getting right on my nerves

Managed to get 2 relays from Maplin yesterday unfortunately they are only rated 10A rather than 15A but a previous post on this thread indicated that should still be OK.

On removal of the CEM one of the relays was actually bulging so clearly something wrong with it.

Took me about 2 hours of fiddling to successfully de-solder and remove the old relays and then solder the new ones in.

Thought I had got a result when I plugged it all back in, ignition on, turned the lights on and went to the front of the car and saw them lit up

Unfortunately on turning off the switch and removal of the ignition key the headlamps stayed on !

So either the 10A relays arent up to the job and are permanently stuck on, or the CEM is knackered. Can anyone advise if the relays are too low amp-rated would this cause them to stick on regardless of whether the switch/ignition is on ? If so I can re-order the correct ones from RS - otherwise I Think I'm going to have to get to a breakers tomorrow and try and get a replacement.
I've been driving round all day with the headlamp circuit disconnected at the CEM - thankfully the brake lights and indicators seem to be controlled separately but I have no main beam with it unplugged and naturally can't drive it in the dark.

Does anyone within a sensible travelling distance of Cannock have a spare CEM I can try tomorrow ? 2000 Model V40 1.8 ( the date on the CEM I have is 10/99 )

what i would do is take the relay out , run 2 thin wires and two thick wires from the solder pads to the outside of teh casing and solder them to a conventional 40A relay and bond it to the CEM casing or fit it somewhere convenient , end of problem forever ...

[caprirob]

I spoke to an Auto Sparky mate and he reckons the Maplin relays are just wrong.
Have ordered the correct ones from RS as per earlier posts on this thread - should be here Wednesday.

Also had an ebay breaker contact me and offer me a box from a '99 1.6 V40 for £15 posted which I will take as well just in case.

I will have to get round the problem until then by driving round with the lighting circuit unplugged, and the under-dash panel removed so I can just plug the lights in if I need to drive in the dark.

[caprirob]

Properly annoyed now - Relays arrived from RS - desoldered the Maplin relays and re-soldered the RS ones in place

Still no good - as soon as you plug the lights loom into the CEM the dipped beams come on whether the switch is on or the key is in the ignition

I've gone from having no dipped beams at all to dipped beams that wont switch off unless you disconnect the CEM

Looks like the CEM has had it - so :

Are CEM's interchangeable or do i HAVE to get the correct matching p/n ?

If I get one from a higher spec car ( with fogs or twin lights for example ) as mine is basic spec with single lights and no fogs will this matter ?

And does anyone have one that they know works from a V40 not an S40 so I dont have to mess around getting it reporgrammed ?

[gatos]

I think I have one 30896698left, that I can program to whatever you want

[caprirob]

Thanks Gatos - just done a buy it now on ebay for one with that same p/n that the seller says is 100% and has been taken from a V40 so fingers crossed - if it doesnt work I'll be back to you

[caprirob]

I can now 100% Confirm that if you buy the relays, solder them in and it puts your lights on permanently with no keys in ignition or light switch on your CEM has had it.

I can also confirm that a 30859700 can be replaced by a 30896698 as long as its confirmed from a V40 ( if you have a V40 and need rear wiper etc ) and it WILL work

I now have working/controllable lights again

[Clan]

30859700 is superseded to 30896698 and is listed for a S40 RHD 2000-2001 model year . I have one going spare , but unfortunately do not know the condition of it as i cant test it .
send a PM if it is needed ..