CEM-1E04 Lamp Switch Module

[DeeJay]

Thanks guys!

Nick, that link explains a lot so it's a data busbar, effectively. Chris has posted a link for circuit digrams, thanks Chris.

Looking at the listings, mine is May 2000 reg phase 2, so I think I'll be looking at TP3943202 2000 Early Version.

Plenty to get my head round and I don't expect to find a "magic answer" in ten minutes!!

I'll be heading home soon, rain has been on for most of the afternoon so I'll see what happens.

Thanks again.

David

[Wentworth]

Hi All,

Just to let you know that i have fixed this, thanks to Clan's thoughtful comment.

It turned out that the second hand lamp switch module I had obtained was broken. I was able to confirm there was voltage to the switch and activity on the LIN connection using a voltage tester.

A big thanks to all who contributed, especially Clan, also to Lakes Volvo at Wyboston. As soon as I connected another switch and turned the ignition on, normal service was resumed.

So, for the record, if you have a non-responsive lamp switch, very dim backlit display on radio etc and of course are able to read the code, the answer is likely to be the Lamp Switch Module.

Cheers,
Paul.

[ratatatatata]

I have the same issue although i had left the window open overnight and it rained. Does this box have a fuse? I have a volvo v70 2004 2.4 diesel. Any help appreciated.

[Wentworth]

Hi

Could you please clarify exactly what the symptoms are?

There is no fuse in the LSM itself. If the area has got wet I would remove and dry out in a warm place eg airing cupboard etc just like you would if your phone went for a swim.

Please post back with more info.

Cheers
Paul.

[pd154]

Wentworh, hope you got it fixed, I had exactly same issue, repaired by replacing LCM (I think lamp control module), which is apparently the light switch. Remove it by pulling fuse panel at side of dash off, and access rear of this switch through that. Unplug , then release and push out.

Originally Posted by Wentworth

Hi All,

I hope someone can help with the following issue that's come up on my 2002 V70.

Symptoms:
=========
Light Control switch no longer operates the headlamps, fog lights, rheostat or headlamp levelling. Main beam flashes only (as if lights are set to pos 0).

Backlit LCD displays in car (e.g DIM readouts for gear, mileage etc) and Radio are all very dim.

Just to add to the fun/confusion:
=========================
I have driven the car over a rough road and the LCD display lights will brighten again and may stay on until the ignition is switched off then on again. This does not always happen over bumpy roads though.

I recently removed and recharged the battery (thinking that it could be voltage related) and the displays and Lamp Switch worked as normal.... for a single drive, then back to the above.

I have read the codes on the car:
=========================

Codes are:

CCM0021 - Air Quality Sensor
CEM1E04 - Communication with LSM control module Signal missing
PDM0025 - Mirror motor signal missing
UEM0004 - Siren Communication fault

VIDA states that the likely causes of CEM-1E04 are a faulty Lamp Switch Module, or a circuit fault between the LSM and the CEM.

I have swapped out the LSM for a working 2nd hand unit, no change.

Has anyone come across this before and can you give me any pointers before I start pulling things apart to get to the wiring between the LSM and the CEM?

I have searched the forums and can't find reference to this error code above. I would guess that a faulty indicator/beam flash stalk would throw a different code and in all descriptions of this problem no mention is made of the lamp switch being dead. In fact as we know its usually the case that the lamp switch has been set to the 3 o'clock position and so won't hold main beam.

The only other clue I have, bearing in mind that all the backlights are very dim is that maybe the light sensor is dying. This was mentioned in post 9 of the attached query about light functions, but the user is no longer active, so I can't check...

http://www.volvoforums.org.uk/showth...ht=Lamp+Switch

This is the relevant bit:

"So my 04 S60 D5 encountered a similar problem; unable to engage full beam and the cockpit light display was very dim.

Volvo dealer replaced the light sensor and the main-beam switch/sensor thing under the warranty - no questions asked."

I'm wondering whether a failing light sensor could affect the light circuit.... VIDA says:

"If the nightfall sensor is covered, the climate control module (CCM) does not receive any signals regarding light intensity, and the brightness of the LED buttons cannot be regulated"

So, maybe this could explain the backlights being dim, but I can't find any connection to this preventing the CEM from reading the LSM?

Thanks for reading this far... any help or supportive comments would be greatly appreciated.

Cheers,
Paul.