Fuel-pressure regulators on fuel-return-type fuel-injection systems are installed a. at the fuel tank inlet. b. at the end of the fuel rail. c. on the fuel filter inlet. d. on the fuel filter itself. two technicians are discussing engine coolant temperature (ect) sensor diagnosis. technician a says that the correct function of an ect sensor depends on having a properly filled cooling system. technician b says that the voltage measured on the ect signal wire should be low when the engine is cold and high when the engine is hot. who is correct?