Could some experts give me temp gauge trouble shooting 101.

This is an Old 1976 Ford 302, boat.
It's the same as an after market gauge on any car/truck with a 302.
The temp gauge is pegged out even with ignition off.
The light works, so I'm assuming good power and ground connection.
I just dont know how to trouble shoot and find out if it's a connection, wire, short, bad gauge, or bad sender. Where to test or what to test for.

Where would you start and what would you do?

Thanks in advance.

 

the "old style" temp guage is nothing more than a probe on the end of a cable.. the wires only have to do with the light..

we had a autometer guage in the dragster that would not read anything..

the probe is bad
autozone for less than 30$ you can get a replacement guage..

installation is very easy

just use a little teflon tape on the threads....

...zap!

 

Maybe it's not that old.
It is an electrical sending unit.
The gauge has 4 post plus ground to body. (mounted in plastic faceing on fiberglass boat, hard to get ground)

Since the gauge is pegged hot, past all readings even with out power, I'm thinking gauge. I just want to make sure before spending anything.

 

if the gauge is pegged with no power then the gauge is bad.

if the gauge doesn't move, ground the wire on the sender. this will peg the gauge.

 

Thats what I was thinking too.

Yes it's pegged all the time, power or not (unless there is a short giving it power full time) I dont think so though. Maybe I should check that Just incase.

 

maybe you should get a real mechanicalguage and stop all the guesswork...


so hows life matt?


...zap!

 

Life is really good, taking a break for a while. Atleast til July 12th.
Been supper busy, need sometime to get caught up on personal things, the house, vehicles, etc.

Alright here is what I found on the gauge, laying down looking under the dash. I located and indentified the ground and the power. I was wrong earlier, there are only 3 connection, I am assuming the third is from the sender. With a multimeter set on volts, from the ground to the sender I am reading reversed polarity of 12v. I disconnected the sender wire from the sender and same thing. So I'm assuming the gauge shorted out. On the block with multimeter still on volt, from sender, then grounding to block is +12v with key on it maxed the needle for ohm resistance with cold engine.