KE70 instruments cluster fuel gauge

[Western Revheads]

hey everyone, so I've installed a new tacho instruments cluster into my ke70, it had the good'old quartz clock cluster, and everything works, but the fuel gauge, I don't remember if the old one worked (still have in just encase there is part failure), but I've taken out the rear tail-lights cause I'm doing rust repair, and I noticed that the fuel gauge wasn't moving and staying in the off position, when the car is running, all the other things in the cluster work cause Toyota just used a standard wiring loom for all KE70's. 

so the question is, does the fuel gauge wire run though the tail-lights wiring? not 100% sure. and I can't find a wiring diagram that says anything about it, so if anyone knows please let me know.     

I know that the loom in all together all the way to the back of the car where it splits of to the fuel pump and lights, and the lights split off the right light so does the fuel gauge work the same way.

so is it a parts failure or a plug not being plugged in. I really don't want to take the cluster surround out again

wiring loom split for lights (top plug) and fuel pump (bottom plug)

 

 

 

 

[altezzaclub]

Take the wires off the fuel sender unit on the tank.

Short the guage wire to earth and turn on the key, the gauge should go to 'full'.  If it doesn't, the problem is not the unit.

If it does go to 'full' the problem is in the tank unit. Take it out of the tank and put your $10 multimeter on the contact for the fuel level arm and move the arm, it should show a changing resistance.  If it doesn't then the problem is in the arm resistance winding. They are pretty dodgy, I think they work occasionally but that is enough to keep the heavily damped gauge needle in place.

I'd expect it to be a bad contact or a broken wire rather than in the tank.

 

[Western Revheads]

thanks man I'll try it after work on sunday

 

[Western Revheads]

Okay so I'm a massive idiot, and I decided to maybe test the theory that perhaps the fuel pump and fuel gauge wires uses the same ground before doing all the testing stuff and it turns out that the tail-lights and the fuel pump/gauge all use the same ground, didn't think of it when I posted the for help. 

 

THE MORE YOU KNOW

So next time check for grounding.