anyone had this problem!!!

I dont go out very often at night but the other night had to pick my son up a couple of miles from home. Anyway on our way back i cut through our estate lots of cars parked at either side of the road. So a lot of slowing and accelerating steadily i noticed when i slowed down my lights dimmed slightly when i speeded up they became slightly brighter strange on a 06 car so i parked in garage and loaded system ie; all lights then rear window demister didnt dim lights at all. only seems to dim lights when moving slowly! can somebody anybody try this for me and let me know how it goes in 1st gear gently going about 5 miles an hour then just take foot off accelerator then speed up again and do the sAME AGAIN FOR ABOUT 50 ORSO YARDS all the time watching the brightness of lights just normal lights!!

I have this same thing happening on my 51 non turbo diesel, I don't know if I would call it a problem though.

On a Diesel the brakes are Pump driven rather than Servo assisted such as on petrols. This adds pressure (for example the same as air con does when you turn it on) to the system of belts etc. which in turn means the engine has to work slightly harder. I find that when I brake slowly before I come to a stop the car's rev's dip slightly and you feel it until the electric idler kicks in and keeps it at a normal level again. Because of this the Alternator won't be turning quite as fast for that time thus outputting slightly less amperage that could cause the lights to dim slightly as they are a high power system. I have not noticed them dimming, but I do notice if you start the car and turn your lights on straight away, it takes around 10-20 seconds for the alternator to kick in properly and the lights "brighten" up.

My lights don't dip either, but when I press the brake pedal the revs dip, in fact sometimes she sounds like she's going to stop but I know she never will cos that JTD engine kicks ass.