Join Date: Dec 2008
Location: Tyler, TX
Thanked 407 Times in 347 Posts
I *think* you have what is referred to as an "Idiot Gauge". Meaning that the "gauge" either reads above about 7PSI (normal) or Zero, and is NOT a true gauge that varies with changing pressure.
The "gauge" is activated by a pressure SWITCH (not sender), Ford has been doing this for 20+years on most every model.
Honestly, I am not 100% sure about the late model PSDs, but I know the earlier ones were this way (with a fake gauge).
'93 F-250 HD, 7.3L IDI, 5spd - FARM TRUCK
I Support: Trailer brakes an every axle over the towing vehicle's GVW; CDLs for RVers; Safety inspections for ALL vehicles and 6 axle trucks (97K GVW proposal).
Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote - Benjamin Franklin
I vote for LIBERTY!