I performed the glow plug relay mod to my 06 and the glow plug light is on for a normal time but this cold morning it seemed that it had none of them working and started real hardI then tested the fuse block for voltage this eve after work with engine cold and it seemed to have no power. Is there some thing else that runs the relay that could be bad? I reafed on all mt solder joints to make sure of good connection when doing the mod......the only thing I wonder about is that their was 6 links in the relay so I relocated all of them not knowing which one was the rite one to leave????? Love my Sprinter.......when it doesn't need work when is that?