Ferguson TO20 temperature gauge

[rsoyring]

Hey guys looking for some help on replacing the temperature gauge on my TO20 not sure exactly what wires went were as there all chewed up by mice. On the new temperature gauge it has two threaded bolts that come down on each side a wire to the probe and then one little connector looking piece? Just above where the probe goes into the gauge. My question is how would I hook this up, and were do the wires goes? Thanks for any help much appreciated!

 

[TR3driver]

If it's a mechanical gauge (as original), then that's not a wire to the probe. It's actually a very small tube (commonly known as capillary tube), and is rather fragile. You'll want to avoid sharp bends, and secure it against vibration.

Just to give you an idea how fragile it is, my brother-in-law broke a brand new one, just cleaning around the back of the gauge.

The other wire and connector thing is probably for a light to illuminate the gauge. AFAIK the original gauge was not illuminated, but if you want to hook it up, the wire would go over to the headlight switch. Make sure the bulb matches your battery voltage.

 

[rsoyring]

I had just picked one up, the old one is completely junk can?t
even see the gauge due to rust, from what I understand is you
take the long wire it already has attached and that goes in on
the front of the engine block. I assume the gauge needs to be
powered, it appears one wire goes to the ground on the dash
Which would be the pos. It must still need to be connected to
a negative terminal? Where would that wire go I assume it
needs to go through the voltage regulator? And then to one of
the bolts connected to the housing, correct?

 

[TR3driver]

Both of the reproductions I've bought have been mechanical. Meaning they don't need electrical power to work.

 

[203 Industrial]

(quoted from post at 13:53:25 04/21/20) I had just picked one up, the old one is completely junk can?t
even see the gauge due to rust, from what I understand is you
take the long wire it already has attached and that goes in on
the front of the engine block. I assume the gauge needs to be
powered, it appears one wire goes to the ground on the dash
Which would be the pos. It must still need to be connected to
a negative terminal? Where would that wire go I assume it
needs to go through the voltage regulator? And then to one of
the bolts connected to the housing, correct?

oes the wire going io the probe have rubber insulation on it. If not its not a wire. Its a hollow copper tube.
As stated by Tr3 Driver.
Its mechanical. No wires required at all for it to operate.
Its a hollow tube that is operated by the temperature change of the coolant expanding the internal air. That increases internal pressure in the tube and moves the needle indicating the temperature.
As stated the only thing the wire could be for is to wire a light bulb to see the gauge at night.

 

[203 Industrial]

Don't bend that tube/wire going to the probe sharp or treat it like a wire. Its fragile and easily damaged. Carefully coil up excess length in a loose loop. I have never seen an electricaly activated temperature gauge that's sold pre wired.
The short wire on the gauge would be positive wire to the battery if you have a negative ground system. It may nit come with the bulb.

 

[203 Industrial]

'
I can't edit yet.
Your gauge works on the principal in the link

https://www.daviddarling.info/encyclopedia/E/expansion_of_liquids.html

 

[Steve@Advance]

The gauge function is completely mechanical.

The studs on the back are strictly for mounting (and grounding should you choose to install the light socket).

The light is optional, nothing to do with the function.

You will find the cap tube from the sensor to the gauge is just barely long enough to reach, and must be carefully routed in exactly the right path. Be very careful not to kink or twist the tube, use the correct fitting in the thermostat housing so not to crush the bulb.

 

[rsoyring]

The what I believe is a wire going to the "probe" it s flatten rubber "wire" if that makes sense haha. I don t believe it to be a copper tube as it s feels flat inside. Also it came from the store all coiled up tight. It seems weird they would sell it all bent if it s a fragile as you guys are saying. Although who knows these days! Thanks for the help.