500 Two-Stroke Tech

Hi,

There is no power to the water temperature gauge - no temperature reading and no background light - everything else on the bike is working normally - I put a different gauge and sub-loom on but still had the same problem.

Does anyone have an idea what the problem might be ?

Thanks.

Cheers
Paul

Hi.
Background light is independent of the gauge with 2 wires : 1 Black/White (+12V) and 1 Black (ground).
It's easy to check.

Temperature gauge has 3 wires on the back : 1 Brown (+12V) to the connector marked with Br
1 Black (ground) to the connector marked with B
1 Green/Red from the thermo unit to the connector with no mark.
From memory, if you put the Green/Red to the ground, temperature should be at max.

Thanks - I'll check it out this weekend.

Cheers
Paul

Hi,

Some progress - the bulb holder terminals were corroded - so now the background light is fixed

On the back of the gauge there are brown , black and green/red wires - all 3 test to ground with the ignition on and off - however the needle on the gauge doesn't move

What should I do next ?

I am a complete beginner with electrics so it is all quite confusing right now.

Thanks

Cheers
Paul

Hi.
First of all, check that you have +12V on the brown wire with ignition key on.
If not pick a wire directly from the battery to test.
Black wire seems good if it is to the ground.
Once you have +12V to brown connector and ground to black connector, put the green/red connector of the gauge successively to the ground and to +12V : the needle shoud move.
And then check the thermo unit with an ohmeter : it is just a resistor varying with temperature.
Thermo unit is still available from Yamaha, and temperature gauge is easy to find : same model as late 350s.
Let us know what you found.

Hi,

I've done all the checks suggested....

There is no continuity on the red/green wire within the main wiring loom ! The sub loom to the gauge is ok - but the corresponding pin on the connector plug from the main loom is a green/ white wire not red/green!! - I can't see a red/green wire exit the main loom - There is no indicator canceller unit which I think is something to do with the green/white wire ? Perhaps I should put in an independent red/green wire from the sender all the way to the temperature gauge ?

Looks like the main loom has been modified incorrectly ?

Thanks for your help with this - much appreciated

Cheers
Paul

Hi.
Yes it looks ...
So possibly the red/green wire is cut in the main loom and you'll have to rewire it directly from the therm unit
And yes, the white/green is used by cancelling unit. If you don't use this unit, white/green is useless. Just plug the yellow/black male connector near fuse box on right hand side into the black female connector.

Thanks for being so patient explaining this stuff to me. After 12 years doing nut,bolts and painting electrics are a new learning curve.

I'll let you know how I get on - I've ordered green/red colored cable and the connectors to try and make a nice job of it even if not quite standard.

Cheers
Paul

Finally fixed the problem by-passing the wiring loom altogether from the temperature sender to the temperature gauge - earthing this green/red wire does give a full needle deflection on the temperature gauge if anyone else has any problems with this.

Thanks for all the help and suggestions.

Cheers
Paul

That's a good job.