Fuel and temperature gauge not working

[SnakeyeS]

The picture above are my gauges at full operating temperature. The fuel gauge does not work at all, its says full all of the time. The temperature gauge does work but it does not go up to the halfway mark. The level seen in the picture is the highest it will go.

Any idea what's wrong? Bad gauge cluster? Bad thermostat and fuel level indicator?

[Dan3215]

Not totally sure about the fuel gauge, but how many miles do you have on your thermostat, water pump, coolant? I'm coming up on 100k in my '98 and my temp gauge hangs out right about where yours seems to be. I was a little confused about this as I'm just used to temps being higher...as are you...but I'm about to swap a new thermostat and flush and fill coolant before spring gets into full swing, so we'll see if that affects normal op temp. As far as the fuel gauge goes just a few things I would check would be fuses, connections behind the gauge cluster, float, or relay? I believe the default position for the fuel gauge is buried in the E position, so I would assume that it is still getting some sort of a signal....which makes it more confusing, and unfortunately points to a problem with relays rather than the cluster itself

[SnakeyeS]

Water pump and thermostat are originals i believe, car has 120k on it. I'm thinking of going ahead and replacing the thermostat since is easy and cheap to do.

[Dan3215]

Yea thermostat would be a cheap first choice considering if it fixes the problem then you're set, and if not then you changed a part that's probably due anyways! Just to provide some more evidence for the thermostat possibly being the culprit how was heat production throughout the winter? Meaning when you had the heater to maximum was it "HOT" or just "hot"...if you know what i'm getting at? If the thermostat is not closing all the way then the engine is still bleeding off too much heat and never really reaching its full operating temp, which thankfully is the lesser of two evils considering not opening would cause overheating...

[SnakeyeS]

It seemed to be producing enough heat, never noticed a reduced amount of heat or a slow heat up time so that leads me to believe the thermostat is ok but like you said, still wouldn't hurt to replace.

[kelley5795]

My Temp gauge quit working and my coolant sending unit was out as far as I know this has nothing to do with the thermostat if the gauge is not working at all. So I went to Auto zone and got a new one and it did not work right. after I installed the new one the gauge went from cool to hot in a matter of mins so about after 2 of these things, I went to Toyota and paid 35$ for a OEM sending Unit and works great now. I tell you this so you don't waste your time.
a bad sending unit can use more gas
Gives the gauge false readings

Hope this helps

[crazyinga]

Have you resolved this problem? My Tacoma is doing the same thing. The taco and speed work. I'm thinking for both to go out at the same time I need to look at the 12 volts supplied to the dash. Any info is helpful. Thanks