'76 Jimmy Fuel Gauge doesn't work

The fuel gauge on my '76 Jimmy doesn't work. It just says it's on full all the time even though I ran out of gas once.

Also the temp gauge doesn't work plus the brake light. Just the voltometer gauge works.

Anyone know what I should search for on my truck to find the problem?

For your temp gauge.. check the coolant temperature sending unit or your thermostat..Fuel gauge check the fuel sending unit..and for the brake light maybe a brake light switch or burned out bulbs....Try these and see what you come up with..Or maybe your dash is messed up..