Mazda 2008 tribute, fuel gauge not reading correctly. Replaced the fuel pump and no change. Any ideas?

The fuel level sender is located on the fuel pump hanger assembly. Sometimes the fuel pump, sender and hanger are all individually serviceable while other times the whole unit is replaced as a module assembly. The fuel level sender works by taking a 5 volt reference signal sent by the powertrain control module (PCM), modifying the voltage using resistance based on fuel level, then sending that signal back to the PCM. The PCM then reports the information to the body control module (BCM) so that the fuel level gauge in the instrument cluster can be adjusted accordingly. Fuel level senders are the most common failure for inaccurate fuel gauge readings. When the sender (or module assembly) is replaced, it's important to ensure the float is properly attached to the sender arm otherwise the resistance will not change with fuel level as designed. If this was done properly then there is likely a problem with the gauge or in the circuit between the level sender and the PCM. One easy way to test the circuit and gauge is to unplug the fuel pump; this creates an infinitely high resistance which should bottom out the gauge. Then, a jumper wire can be used to short the two sender wires (the smaller 2 of the 4 wires) to create a zero-resistance circuit which should top out the gauge. You can read more here: https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-fuel-gauge-sender

when a temp gauge drops to cold ,it indicates a problem in the cooling system
temp gauge sender units need water to activate the resistance that makes the gauge read so a falling gauge indicates no water around the sender unit --- air lock in the system--faulty wire connection to the gauge sender unit
the ac unit is not connected to the temp gauge so there may be another separate problem there
the temp sensor is an entirely different unit to the temp gauge sender unit and the short term working would be from an altered coolant level from changing that sensor --air lock in system
the temp sensor connects to the ECM to activate the fans and monitor engine operating temp so as to keep the air/fuel mixture exact for the engine conditions
the temp sender unit just makes the temp gauge read
a faulty thermostat will either be stuck open and the engine temp will take a long time to rise or it will be stuck closed and that will cause an overheat very quickly

its usually the fuel level sender switch in side the gas tank

I think the sending unit was damaged on installation or is defective. Did you use a factory OEM part.

instrument cluster is just for monitoring. but on modern cars there can be integrated circuits to calculate the actual amount of fuel inside tank. so sender sends signals and dashboard decodes it and show the amount on gauge.

which car do you have? if it is a later model with such system you may need to reset related software to match with new sender unit on pump or floater. (dealer can do this for you)

for example if you have a new daylight driving lights(LKM) controller on new BMW's if you replace it with a new one you need to code it to match with your car. if not it wont operate correctly.,

But there is an exeption. when sockets are broken or connections are wrong, fuel and temp gauges act erratic. they jump, pulsate or dont work at all. before replacing anything more be sure that sender unit or whole asembly is the correct part for your car. second be sure that connection has been done correctly.

The wire between the dash and the fuel tank is connected to ground somewhere. there is a control that fails too but if the control failed the temperture gauge also won't work. The wire can get in troble inside the tank too as if someone tried to steal the gas with a hose. if you can disconnect the connector ( wireing ) at the fuel tank and turn the key on and the gauge goes to empty you know the troble is inside the tank and the pump sender unit will need to be removed from the tank to correct the problem or even the gauge unit replaced.

the fuel sender unit ,or the float is full of petrol ,as for temp ?' not sure as its not related as far as i know

Removal & Installation
Through the trunk servicing panel...

1. Before servicing the vehicle, refer to the Precautions section.
   
2. Properly relieve the fuel pressure.
   
3. Remove or disconnect the following:
   
   • Negative battery cable
     
   • Rear package trim
     
   • Service hole cover
     
   • Fuel pump cover
     
   • Fuel pump connector
     
   • Fuel hoses
     
   • Fuel pump and gauge sender unit as an assembly
     
   • Fuel pump from the sender bracket
     

To install:

• New O-ring set
  
• Fuel pump to the sender bracket
  

NOTE

Pull the fuel pump down so that it is tight against the bracket.

• Fuel pump and gauge sender unit as an assembly
  
• Fuel hoses
  
• Fuel pump connector
  
• Fuel pump cover
  
• Service hole cover
  
• Rear package trim
  
• Negative battery cable
  

You're either looking at a short in the wire that goes to the fuel sender, or a bad fuel sender. If it was just a broken wire, it would read empty instead. The fuel sender is a permanent part of the fuel pump, so that has to be replaced as a unit.

Your problem is fuel gauge is hanging up on the fuel pump. The slide bar/fuel sender is located inside the fuel tank alongside the fuel pump. Today I removed my fuel tank and replaced the pick up strainer on my fuel pump and previously my fuel gauge didn't work, but all I needed to do was slightly bend the slide mechanism and my fuel reading read correctly on my gauge. Previous to that I showed no reading on the dash meter.