With the aid of this ‘How To’ tutorial, I"ll display you just how to do it using just a multimeter.

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You"ll have the ability to find out if the fuel pump relay, or the fuel pump Inertia Switch, or the fuel pump is the reason of the No Start condition on your Ford automobile or pickup.

If your fuel injected Ford pickup, van, or vehicle still has actually the Ford relay, this negative boy will be a green color (like the one in the photo viewer). If it has currently been replaced with an after-market one, this relay won"t it is in green, however will have actually a gray body.

The following tutorial may be the help: How To test The Fuel Pump (Ford 4.9L, 5.0L, 5.8L) (at: troubleshootmyvehicle.com).

For your cross reference information:

AutoZone part #:Duralast 19911O"Reilly part #:BWD R647Master pro Ignition 2DR-1039Others:STANDARD motor PRODUCTS component # RY46TSTANDARD engine PRODUCTS part # RY46ORIGINAL ENGINE MANAGEMENT part # DR1039AIRTEX / WELLS part # 1R1294

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you can uncover this indict in Spanish here: Cómo Probar El Relé De La Bomba De Gasolina (Relé Verde) (at: autotecnico-online.com).

What Tools execute I must Test The Relay?

You need a couple of basic things and they are:

MultimeterA digital or analog multimeter will work.Wire Piercing ProbeJumper WiresYou"ll require two that them v alligator clips ~ above both end (you deserve to make these yourself).

Fuel Pump Relay Circuit Descriptions

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The Ford fuel pump relay has 4 wires that attach to it.


Each wire has actually a particular job come do and also these room their circuit descriptions:

IMPORTANT: Your certain Ford automobile may not have actually the precise same colors listed below. This is no huge deal, due to the fact that the circuit descriptions space the same. Friend will be able to use the information in this write-up to diagnose the fuel pump relay on your Ford automobile even if the colour of the fuel pump relay connector"s wires space different!

Ford Fuel Pump CircuitsPinWire ColorDescription
1Tan w/ eco-friendly stripe*Fuel Pump Relay Control
2Red*Power (from EEC strength Relay)
3Brown*Fuel Pump Output
4Yellow*Ignition Fused strength (Fuel Pump Fuse)

* Your specific Ford car may have different colors.

Relay Basics: how The Fuel Pump Relay Works

The core objective of a relay is to manage a high quantity of current with a smaller sized (lower) current. How? You could ask.

Well, every Ford fuel pump relay has actually two an easy circuits and also for the function of ours discussion, we"ll call them:

A high existing circuit.A low present circuit.

Both of these are fully independent indigenous one another, in various other words, voltage/current flow thru" these circuits don"t mix.


The high existing circuit is the one that delivers the voltage (and thus current) to the fuel pump in the gas tank (or top top the structure rail).

When the fuel pump relay is off (not activating the fuel pump), the high existing circuit is ‘open’.

In it"s ‘open’ state present does not get sent to the fuel pump.

The low current circuit is the control circuit that ‘closes’ or ‘opens’ the high current circuit. By ‘closing’ the high current circuit, I especially mean allowing voltage to happen thru" the relay (internally) and also on its method to the fuel pump.

To obtain into much more specifics, this is what happpens when you rotate On the crucial and crank the engine:

Power (in the type of 10 come 12 Volts) is used to circuit 2.This voltage originates from the EEC strength relay.Power (in the type of 10 come 12 Volts) is used to circuit 4.This voltage originates from the ignition switch.The fuel injection computer system then grounds circuit 1.This activates the fuel pump relay to pass present from circuit 4 come circuit 3.Circuit 3 is the one that runs come the fuel pump (via the Inertia Switch) and delivers the voltage/current it needs to activate.Before this voltage will the fuel pump, it needs to go through the fuel pump Inertia switch first.If the Inertia Switch has actually been tripped, it will certainly ‘open’ the circuit and also the voltage will certainly not reach the fuel pump.

As you deserve to see, there"s really nothing facility happening behind the scenes through the fuel pump relay and also the means it activates the fuel pump once you turn the an essential On and also start cranking the engine.

See more: How Would You Describe Bud Not Buddy Bud Character Traits, Bud, Not Buddy Character Analysis

OK, working theory lesson is over, let"s get trial and error in the next page.

Where come Buy The Fuel Pump Relay

The adhering to aftermarket relays space the replacement because that the environment-friendly fuel pump relay: