I have a 1985 hmmvw with an upgraded 6.5 motor 1800 miles I bought it a month ago and haven't been able to Star it. the glow plug wait light doesn't come on at all. I've read a lot of posts and have done the ground harness I've changed the glow plugs and a new KDS smart box with a new matching TSU unit. Still not wait light I've metered the wait light have 24vdc. With the key in the wait light position I get 3.68 vdc to each glow plug. When I put my meter to the battery red lead on the positive and black lead to each glow plug I get 24vdc. I don't know what else to do or am I missing something. This is the fist post I've done. Read a lot and did a lot of things before I wrote this. Need some help.