Leaks are your first clue, and the operations of the device your using it for, slows down or is not as powerful.
how do i know the fuel pump is going bad in a 1998 ford expedition eddie bauer?
check the the pump pressure at the rail
When a fuel pump is bad the vehicle will not start. A fuel pump that is going bad may cause the vehicle to shut off while going down the road.
It is rare for a water pump not to work however a water pump going bad will leak coolant and can be noisy from bad bearings.
Noisy pump, hard starting, stalling.
You just don't know until a mechanic tells you.
In most cases the water pump will start to leak coolant when it is going bad.
Hard starting, stalling and eventually it simply will not run. Change the filter before assuming the pump is bad.
If the fuel pump becomes noisy you can rest assured it is going bad. But, the pump maybe going bad and not make any noise at all. Anytime you have a problem with fuel delivery, first thing to do is replace the fuel filter. After replacing the fuel filter a fuel pressure test will verify the condition of the pump.
In most cases the pump will start leaking coolant out of the weep hole and or you may hear the pump bearing going bad.
You will hear valve train clatter.
Swap the relay with a another like relay.