Hi there, I know I've asked this before but I am desperate for some guidance! A6 quattro estate with 2.5Tdi (5 cyl) engine I think code AEL. Glow plug light comes on & goes out after a few seconds, takes longer when really cold so seems to be working. But no power gets to glow plugs. If I connect glow plug directly to battery it glows, If I turn on ignition it receives no power (proven by unscrewing glow plug & earthing against engine block). where do I look - relay, fuse etc.