Anyone know how many volts are (supposed to be) sent to the water temp switch? Getting 12 volts at my sensor, which controls cold idle speed solenoid and cold timing advance. Incidentally, when I bypass the water temp switch, via a jumper wire, I don't notice any difference in idle speed or if engine has advanced. Only schematic I can find is for a 1990 F250 diesel...

 

You might get a lot more answers in the correct diesel forum, but I'll leave this post here just in case.