Other 70 Problem: DIM or CEM fault?

[tnewey]

Hi,

I have some electrical gremlins with my 2000 (new shape) v70 - I am hoping that someone may be able to help track down whether it is the DIM or CEM I need to take out and fix!

Symptoms are:

-Start engine and instrument panel illumination stays off for several seconds before coming on (warning lights work as normal)

-Radio / CD player works but no display or backlights to controls

-Controls for climate control switches very dim

-No backlights on auto gear selector

-Instrument panel clock, odometer and message display very dim, but appears to work OK

-Headlight switch does nothing and appears to have no power - the daylight running lights are always on whether you select sidelights or night running and the main beam wont stay on in any setting.

The car runs and drives fine otherwise with no messages or warning lights.

From my search of the forum I suspect the DIM or CEM, but before I tear the car apart, which should I target first!?

Regards,

Tris.

[RAN60]

Sounds more like CEM than DIM. The DIM doesnt control any of the steering wheel controls or the light module. I could be wrong but id be looking more towards the CEM???

Have you checked for water ingress? might just have been on older models.

Idealy you need to have the error codes read.

Rich

[spokoluzik]

I would simply start from light switch.

[Missing Lincs]

As spokoluzik says, all symptoms point to the lighting switch module.

The DIM encodes the signals from the light switch module but it does sound like the module itself my be the source of the problem.

Does the headlight levelling control work?

If you can get a cheap replacement from a scrappy it would be an easy way to test if it is the light switch module. Just make sure its off a donor with similar age/model year.

[Clan]

yes get a used light switch , they are not software coded .

[tnewey]

Thanks for those suggestions. Would a duff lightswitch affect the radio switches and heater control lighting on the cetntre console too through?

Headlight levelling doesn't appear to work and no fog light either - it appears there is no power to the unit at all.

Cheers,

Tris.

[Clan]

Originally Posted by tnewey

Thanks for those suggestions. Would a duff lightswitch affect the radio switches and heater control lighting on the cetntre console too through?

Headlight levelling doesn't appear to work and no fog light either - it appears there is no power to the unit at all.

Cheers,

Tris.

yes all the lighting is controled by the light switch module .

[tnewey]

Problem fixed - it was the light switch. I found evidence of what looked like burning around the sliders for the headlight level and instrument illumination level controls. Alarmingly, the replacement second hand part (£10 from e-bay) looks in worse condition - with white deposits on the circuit board looking like its had water on it at some point. However, it works OK, so fingers crossed it will last a while yet!

[itllbemethen]

The "light swith module" ...as in "the switch" itself ?

I have the "same ish" problems.

On starting the dash is working, but not lit. The light then comes on (but dim).

The dashboard controls all function correctly (revs, speedo, temp, fuel etc, etc and data board)

I have no "main beam" (with the switch in the correct position) the main beam comes on, however when the stalk is released, the main beam falls back to dipped.

I have no front fogs.

Oddly (hence why would it be the light switch) the centre radio/cd console is not lit, but does work. (No idea what track on the cd was good !).

Having had the ETM fail (replacement from Canada) I was expecting some "massive, key, oh so expensive module" to be causing this fault...(CEM or DIM) but are you saying it's the "light switch" that is at fault ???