Checking temp gauge operation?

[rusty ol ranger]

Pull wire, ground wire, and gauge should jump correct?


I grounded the wire to the battery with a test light and the gauge didnt move but the test light blinked?

Usually i dont care, but on a 2.9 i do.

 

[RonD]

Turn key on
Unplug temp SENDER wire
Look at the gauge, should be below COLD or above HOT

Ground the wire, no test light, gauge should now be opposite of above

Generally speaking with wire unhooked gauge should be below COLD
Grounded above HOT
But it can be opposite, depends on how it was wired that year, this wiring is a "fail safe", if wire comes off gauge goes to hot, causing driver to check engine, "normal" wiring when disconnected shows cold so engine could overheat without driver noticing right away

That tests wire and gauge
If it tests OK then replace SENDER

You will almost always be given a SENSOR first time out, tell them SENDER repeatedly

Easy to tell the difference, sender is 1 wire, sensor is always 2, but some senders had 2
Lower part of SENDER will look like a cylinder, sensor looks like a cone

 

[rusty ol ranger]

Turn key on
Unplug temp SENDER wire
Look at the gauge, should be below COLD or above HOT

Ground the wire, no test light, gauge should now be opposite of above

Generally speaking with wire unhooked gauge should be below COLD
Grounded above HOT
But it can be opposite, depends on how it was wired that year, this wiring is a "fail safe", if wire comes off gauge goes to hot, causing driver to check engine, "normal" wiring when disconnected shows cold so engine could overheat without driver noticing right away

That tests wire and gauge
If it tests OK then replace SENDER

You will almost always be given a SENSOR first time out, tell them SENDER repeatedly

Easy to tell the difference, sender is 1 wire, sensor is always 2, but some senders had 2
Lower part of SENDER will look like a cylinder, sensor looks like a cone

Yeah i went thru the sender/sensor BS when i changed the one (sender) on my 97 460.

Ok, so ground it with no test light, just a wire. Thanks

 

[RonD]

Yes, sender is a resistor, test light is a resistor(bulb), you want to remove the resistor and go directly to ground, it's not a "short" since the gauge is in the circuit.

 

[rusty ol ranger]

Gotcha, thanks bud

 

[rusty ol ranger]

Ok, ill check it out this afternoon. Wanna make sure its working before i drive it and fry a head.

 

[rangerenthiusiast]

RonD, you just helped two people on one thread. The gauge on my ’92 4.0 Ranger barely moves above cold, even when it’s blasting good heat. Been meaning to test the gauge and sensor since I got it. Sorry to interrupt your thread, ‘Rusty.