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Hi all, could someone tell me or post pics to explain which way round the two wires go at the back of the temp gauge please? Mine has 3 male blades, two close together and t’other on the other side, and an earth wire presumably from the framework holding the gauge in place? So where does the green/blue connect?

Refer to the Haynes manual or another good wiring diagram.

The gauge sits in series between switched battery voltage and earth through the sender.

The double blade allows for the switched battery voltage to branch to another application. The clamp is not in circuit as far as the gauge is concerned but depending on the wiring connector for the illumination, may carry the bulb current to ground.

Another thread, but it might help…….number 14 on the key
I think it written in Australian, so a “Thermo” is a Temp gauge, isn’t it ?

viewtopic.php?p=60434#p60434

Jason .. you have very good advice from Garry .. why dont you look at The Wiring Diagram items 46 & 47 where all will be seen
Green/Blue Wire from Gauge to the Temp Sender ..The Light Green Wire from back of Temp Gauge onto terminal "I" on the voltage stabilizer.

I’ve been reliably informed that it’s possible that this car (March/April 64) may not have a voltage stabiliser fitted? In that case where’s the green wire attached to? Mmmmmmm ?

The green is the live coming in to the gauge and the green blue comes off the gauge goes off to the thermostat.

If yours is a non stabilised gauge there will not be a voltage stabiliser screwed to the back of the clock, also there will not be any connectors to allow connection to the voltage stabiliser

Make sure the gauge is earthed using the black wires, if in doubt rig up a temporary earth between the gauge and the body

Here are the wiring diagrams for both, you are looking at 14
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.
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Jasonking wrote: ↑Fri Nov 15, 2024 12:14 am I’ve been reliably informed that it’s possible that this car (March/April 64) may not have a voltage stabiliser fitted? In that case where’s the green wire attached to? Mmmmmmm ?

This was mentioned previously, if your fuel gauge is still working, when you switch on the ignition does the needle immediately flick up to show the level or does it rise very slowly ?. If the latter is true you have a stabiliser, if the former then you don't.

111Robin wrote: ↑Fri Nov 15, 2024 8:43 am

Jasonking wrote: ↑Fri Nov 15, 2024 12:14 am I’ve been reliably informed that it’s possible that this car (March/April 64) may not have a voltage stabiliser fitted? In that case where’s the green wire attached to? Mmmmmmm ?

This was mentioned previously, if your fuel gauge is still working, when you switch on the ignition does the needle immediately flick up to show the level or does it rise very slowly ?. If the latter is true you have a stabiliser, if the former then you don't.

Or simply look at the front of your speedo for the dark 'jewel' centre top as I posted previously, as the blanked out light is where the stabiliser is fitted on the later 64 on speedos, so the layout is different.

Do let us know how you get on and whether you have solved it or not.

My Speedo has the blank dark jewel light at top of the unit facia, so voltage stabiliser is fitted?

Just turn on the ignition and see what the fuel gauge does. Your car may not be factory original so you can only tell by how the gauges react.

Jasonking wrote: ↑Fri Nov 15, 2024 6:28 pm My Speedo has the blank dark jewel light at top of the unit facia, so voltage stabiliser is fitted?

If you take a photo of the back of the speed, from in the engine bay we may be able to see…..

When switching on ignition, fuel gauge flicks immediately to show tank contents and back to zero when key turns off? So does that mean no voltage stabiliser fitted?

Jasonking wrote: ↑Sat Nov 16, 2024 7:14 pm When switching on ignition, fuel gauge flicks immediately to show tank contents and back to zero when key turns off? So does that mean no voltage stabiliser fitted?

Correct

Ok, have installed new s/hand gauge and absolutely no movement whatsoever on gauge needle when ignition switches on, at least original moved slightly to Cold, but wouldn’t move any further regardless of engine temperature, what if the two wires are on the wrong terminals, would that make gauge appear dead?

What’s the part number on the gauge? Is it a stabilised gauge?

Do you have a multimeter?

You need to establish a few things;

1. A 12v live feed to the gauge.
2. Continuity from the sender to the gauge
3. That the sender shows a resistance that falls as it gets hotter. There’s some very useful information here about gauges and senders https://www.triumphclub.co.nz/wp-conten ... _2_2v1.pdf. You could measure the resistance from the terminal of the sender to the sender body (the nut head would be a good place) and again from terminal to a clean point on the block. Should be no difference. If there is, you’ve got insulation between your sender threads and the cylinder head (your PTFE tape)
4. That there’s continuity in the gauge itself. Applying 12v across the terminals should make the needle flick all the way to hot.

If you’ve established a live feed you could place your multimeter in parallel with the gauge and see what the voltage is. As the engine gets hotter, the voltage will rise. This proves out the wiring to the gauge and down to earth via the block. Low volts cold, high volts hot.

These tests should indicate

- a failed gauge
- a failed sender
- a failed wiring connection

There really is nothing else in the circuit.

Hi, thanks for that, yes have multimeter but just use it on 20volts to check batteries, so no clue what else it does. Removed ptfe from brand new red top sender so that should work hopefully.

The red sender GTR104 is for stabilised gauges
You’ll need a GTR102 for non-stabilised

Here’s some previous info about the resistance ranges of the various senders at different temps

viewtopic.php?t=19902

Would anyone know the oe smiths part number on the green temp transducer for non stabilised gauges, ie: GTR102? Thanks.