97 F350 7.3l, 120k: Hooked my m/meter up got 12.5v on the black/orange wire post, then checkotherstuds nothing. ThenI turn the key on without turning engine over, then rechecked with on got voltage on black/orange wire and on one little post(rear), (front post) had .5v, tap relay screwdriver front went to 12v, but no reading on the other big post. Question is, with the key on shouldI have voltage on all post?

PS: thanks to this web site I found out it has a heater at the oil filter housing.

 

With the key on you should have power on all the posts. The large terminal with the 2 brown wires coming off it goes to the glow plugs. It should only have power for a short while. The glow plug relays are know for going bad.

 

Went got a new glow plug relay, works great.

 

Thanks