[Kyle Leckey]

My fuel gauge has never worked on my 71 fj55
I do know that some one cut the wire under the hood next to the fuse box.
so the question is...... what is the bunny trail that I should take to find out what is the problem and how do I fix it?
thanks

[Kyle Leckey]

anybody..?.?? Bueler...Bueler????

[Tobugrynbak]

Having had a look at the FSM for FJ55 (USA & Canada) - 1979 model. Also the diagram for non USA & Canada models (no date.)

The wiring diagram says that the wire is Yellow with a red stripe which runs from the instrument cluster to the sender and another wire which is White with a Black stripe goes from the sender to ground.

On the back of the FJ55 Temp/Fuel/Oil cluster, as well as the FJ55 Temp/Amp/Fuel/Oil cluster, the Yellow/Red wire should connect to pin 8 which is the top left pin.

I'll list the pins, purpose and wire colours below.

Pin .. Purpose .............................Wire Colour
1 ......To oil Pressure Sender ........Yellow/Black
2 ......From ignition power feed .....Light Blue/Red
3 ......Ground ..............................White/Black
4 ......Dash illumination ................Red/Black
5...... Park brake light ..................Red/White
6 ......Charge light .......................(can't find it)
7 ......Temp Gauge sender ...........Yellow (or Yellow Green)
8 ......Fuel Gauge sender .............Yellow/Red

Hope that helps.
Cheers
Perry

[FJROSS]

Just to rule out another possible problem, check the circuit board on the back of the gauge cluster and make sure there's no damage to the copper tape. This area is supsetable to damage when removing and installing the gauge cluster with the steering wheel in position. After checking my grounds and replacing the fuel sender, my last resort was to replace the gauge. That's when I found that the copper tape on the rear of the circuit board must have been damaged and a half-*** repair done by a previous owner (the butcher) with some solder, which didn't work. I ended up switching gauge clusters.

Dave

[Tobugrynbak]

Some quick basic checks you can do to see where the problem lies.

Disconnect the wire that goes to the sender and connect it to ground. Now turn on the ignition. If the wire to the sender is intact, and the gauge is working then the needle will swing to the Full mark. If that's the case, then the problem is in the sender/ ground wire.

If you have a multimeter, check that the sender body is grounded by measuring the impeadence between the sender body and any handy chassis/body point. i.e. seat mount bolt. The impeadence should be very low, under 1 ohm.
If you have an open circuit, then the ground wire is not attached to a ground point, could be faulty or missing.

The fuel sender has a total impeadence (resistance) of 120 ohms +/- 6.5 ohms when the tank is empty, and 17 ohms +/- 2.1 ohms when full. It should have something like 40 ohms +/- 4.5 when the tank is half full. If you don't get any measurement with your multimeter then the sender is faulty.

See how you go with that lot.

Cheers
Perry