Youdidn`t say Fuel Pump Relay, did you? You said Fuel Relay Switch This is a technical forum after allit`s helpful when people use the correct nomenclature. 1989 FLSTC, 2016 FLHR 2019 FLHT, 2022 FLHTCTGU US Navy Veteran 1974-1979 (AD2) FAA A&P Mechanic since 1980. Reply. Save. CirculatorPump Relays: 1 of 3 alternative ways to control hot water heat circulation. The aquastat is the most common control of heating system boilers. On a call for heat the thermostat, connected to the aquastat primary control, will operate a circulator control relay inside the aquastat to turn on the circulator pump, or on some systems the Youcan test the relay with a 9 volt battery to see/hear if it clicks. Testing the fuel pump for operation. With the relay out of the coupler, use a jumper wire between the white wire and the black wire in the coupler. Disconnect the fuel pump outlet @ the three way joint, catch the fuel in a container, turn the key on for about 5 seconds and 12.1 Faulty fuel pump relay; 1.2.2 Blown fuel pump fuse; 1.2.3 Faulty ECM; 1.2.4 Bad cam or crank sensor; 1.2.5 Poor battery supply voltage; 1.2.6 Immobilizer switching off the fuel pump; 1.2.7 Faulty spark plugs / ignition Coils/ Bad Ignition switch; 1.2.8 Bad starter motor; 2 Conclusion Thefollowing tutorial may be of help: How To Troubleshoot A No Start (GM 4.3L, 5.0L, 5.7L). CASE 3: The engine started and stayed running. This confirms that the fuel pump is starting to fail. The next step is to confirm the exact fuel pressure with a fuel pressure gauge to be absolutely sure. Anotherpotential cause for bad fuel pump symptoms is a faulty fuel pump relay. This relay controls the power supply to your Charger's fuel pump, and a faulty relay may lead to: Intermittent power loss to the fuel pump. Inability to start your car. Unpredictable pump operation, leading to stalling or rough running. DHFIM.

when a fuel pump relay is bad