coolant temp sensor still not working

[SomeOld96GT]

so i have a 96 gt which i recently swapped the engine with my dad for a 98 4.6 2v, ever since we did the swap the coolant temp gauge hasn't been working, so i took the gauge cluster out for maybe just a bad connection, nothing, got a new sending unit still nothing, even checked that connection for maybe corrosion but it was clean.

 

[ttocs]

well it sounds like the only choice left is to trace the wire back and look for spots that are exposed/bare or if you can tell the wire has corroded. An ohm meter can help you test if you can find the beginning/end of the wire.

 

[Miltoid]

Disconnect the wire with ignition on, does the gauge move? Now ground the wire, does the gauge move? If the gauge doesn't change you have an open in the wire or the wrong wire. I can't remember if grounding makes the guage go full hot, but one of these operations should make it go full hot if the wire and gauge are good.

 

[cobrajeff96]

Correct, grounding the signal wire will make the gauge read full hot (zero resistance straight to ground).

But at some point in the SN95 series, even the coolant gauge went to two-pin. This might've been 99+ but I can't be sure.