1952-59 Ford Tempture Sending

how can i test to see if my tempture sending unit is working on my 55 ford

 

This verbatim from the 1953 shop manual. It will still apply as no substantive changes were made to instrument operation between 1953 and 1955.

Turn the ign switch ON and observe the temperature gauge (engine should be at operating temperature). Follow (a) or (b) below, whichever applies.

(a) INDICATOR AT THE "C" POSITION ALL THE TIME.
This symptom indicates a short in the gauge circuit or a defective gauge. To check the circuit, proceed with steps (1) through (2) below.

(1) Disconnect the wire leading from the sending unit to the gauge (disconnect at the gauge). Turn the ign switch ON. If the indicator remains at "C" replace the gauge. If the indicator moves toward the "H" position, a short exists in the wiring from the gauge to the sending unit. To determine where the fault lies proceed with (2) below.

(2) Connect the wire at the gauge and disconnect the wire at the sending unit. Do not ground. Turn on the ign, and if the indicator registers at the "C" position a short exists in the wiring between the gauge and sending unit. Repair or replace the wire. If the indicator moves toward the "H" position the short is in the sending unit.

(b) INDICATOR AT THE "H" POSITION ALL THE TIME.
Start the engine and observe the gas and oil gauges. If they are inoperative, correct the power circuit from the ign switch to the instruments. If the gas and oil gauges are operative see (1) below.

(1) Momentarily short the wire from the sender to the gauge at the gauge. If the indicator stays at the "H" position replace the gauge. If the indicator moves toward the "C" position, an open circuit is indicated. Proceed with (2) below.

(2) Disconnect the wire from the gauge to the sending unit. Turn the ign ON and momentarily short the wire. If the indicator stays at the "H" position, an open exists in the wire leading from the gauge to the sending unit. Repair or replace it. If the indicator moves toward the "C" position proceed with (3) below.

With the ign switch ON, momentarily short the terminal of the sending unit. If the indicator moves toward the "C" position the sending unit is defective.

 

The 55 gauge is the last 6 volt car gauge that Ford used and it is backwards from 57 and later gauges, that is it goes to "H" when you turn the car off where the others go to "C". I tried to find a chart for the sending unit that showed ohms / temperature so I could check it at several different temperature readings but had no luck finding such chart for the sender. It is completely different than a 302 unit as far as the ohms cold reading but I don't remember the exact values. The Y Block sending unit is also quite long, it just barely fit into the hole on my Edelbrock manifold. Diameter is the same but it sticks down in the hole and hits the bottom of the coolant passage in the manifold. Now that I have converted to 12 volts it the gauge seems to read higher than it did in the Y Block 6 volt at the same temperature.

 

Try the Yblocksforever website. Is the sender Located in the drivers side cylinder head behind the end of the intake.? A 55 6volt owner here should be able to tell you the ohms to ground reading if any.