You are watching: 1995 ford ranger fuel pump relay location
Hey guys i am trying to diagnose why fuel pump won"t turn on. If I apply 12v directly to pump out of tank it turns on. But only getting 6v when I put the meter on the plug that connects at top of the unit. I get 6v to and from the inertia switch. Could it be the relay is only sending half the needed voltage or is something else wrong. Please help.
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What year?The 5 to 7volts has no amps, it is from the computer.The Computer turns on the fuel pump relay and then monitors if it did come on, that circuit will bleed 5 to 7 volts when key is on but fuel pump power is off.But it has no amps so can"t run fuel pump.And yes that computer wire, with the 5-7volts, is usually connected to one terminal of the inertia switchWhen you turn on the key the computer Boots up and GROUNDS the fuel pump relay for 2 seconds, and 2 seconds ONLY.Computer will not turn on fuel pump relay again until Engine RPMs are above 400, engine started.But you can cycle the key off and on as much as you want when testing, it won"t hurt anything.(If wondering why it only runs for 2 seconds, it is a safety issue, it prevents an electric fuel pump from continuing to pump out fuel from a broken fuel line, i.e. line breaks engine stalls, RPMs under 400 power is cut to fuel pump)Power for fuel pump goes like thisBattery----30amp fuse-------Fuel pump Relay----------inertia switch------------fuel pumpFuel pump relay is not expensive, $5-$8Inertia switch can be reset with button on the top............but once inertia switch OPENS, it must be replaced, reset button is there so vehicle can be moved after an accident, it will never fully "reset".Relays have 2 partsLoad, in this case the two Load contacts touch together to send 30amp 12volt power out to fuel pumpCoil, this is the low amp side, when coil has 12volts and a Ground it becomes and electro-magnet and pulls the Load contacts together and holds them together until coils 12volts or Ground is cutFuel pump relays "coil" gets power from EEC relay, when it closes(key on) EEC relay sends power(12volts) to EEC(computer), fuel injectors, spark system and fuel pump relays coil.So Computer can GROUND the other side of the coil and relay will close and send power to inertia switch, and then fuel pumpIf you want to test relays socket pull out the relayKey offtest each slot for 12volts, one will have 12volts, thats power from the 30amp fuse, connected 24/7(all the time)Now turn on the keytest slots again, another slot should now have 12volts, this is power from the EEC relay, the coil power