What does the YWC106950 do? by Ian@Dedham

My lights are "flashing" with the fault being traced to the light unit part ref YWC106950. I have been trying with absolutely no luck to source a replacement.

I am told that the part needs to be new to "pair" with the car. But why? what does YWC106950 actually do that requires pairing and why should I not be satisfied with a second hand part?

Are there any alternative parts that I could use?

Anyone got any ideas?

Posted 24 Mar 2013, 20:04 #1 


Posted 24 Mar 2013, 20:07 #2 

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The mileage is stored in the LSM (Light Switch Module) (light switch module) if you use a 2nd hand unit you will get a error message on your IPK (Instrument pack (IPK from the German)) (speedo) as there will be a mileage mismatch between the LSM and the IPK.

I believe that member Monk with his T4 (Testbook version 4.Computer Diagnostic System) can reprogram a 2nd unit to work with the car so no errors are shown.

Hope that helps.

Posted 24 Mar 2013, 20:38 #3 

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Sorry I forgot to welcome you to the forums.

Welcome :)

Where are you based as you might be near to someone that we can put you in contact with that could offer some help.

Posted 24 Mar 2013, 20:41 #4 

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If you use a second hand unit then you get ERR in the trip as Andy says. However that only happens while the non matching unit is plugged in so it could be worthwhile borrowing a second hand unit to prove it fixes the problem.

To be honest it's more likely a wiring problem somewhere, but a second hand unit would tell you for sure.

Posted 24 Mar 2013, 20:52 #5 

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Might be worth just getting the front panel of the LSM and changing that... it doesn't require reprogramming and is a simple swap.

EDIT: just noticed that the link you provided is just for the front panel, not the full LSM. Overpriced at £30, you should be able to get one for about a tenner, and 2nd hand is fine.

EDIT: here's a 2nd hand one for just over a tenner, take off the front panel and try it on your car.

2004 MG ZT+ CDTi 135


Posted 24 Mar 2013, 22:04 #6