Rennlist 944 Fuel Pump Relay Diagram

January 16, 2012 Updated: March 20, 2021 Past: Abraham Torres-Arredondo Clause ID: 121

Testing the Ford fuel pump electrical relay on the auto is not that hard to do.

With the assistance of this 'How To' instructor, I'll record you how to get along it using only a multimeter.

You'll be able to se if the fuel pump relay, or the fuel pump Inactivity Switch, operating room the fuel ticker is the cause of the no-get down train on your Ford car OR getaway.

If your fire injected Ford pickup, van, or car stock-still has the John Ford electrical relay, this bad boy will be a K color (like the one in the look-alike viewer). If it has already been replaced with an afterward-market one, this relay won't embody green, but will have a gray body.

The following instructor may be of facilitate: How To Test The Fuel Pump (Ford 4.9L, 5.0L, 5.8L) (at: troubleshootmyvehicle.com).

For your sweep reference information:

1. AutoZone part #:
   1. Duralast 19911
2. O'Reilly part #:
   1. BWD R647
   2. Master Pro Ignition 2DR-1039
3. Others:
   1. STANDARD MOTOR PRODUCTS Part # RY46T
   2. STANDARD MOTOR PRODUCTS Part # RY46
   3. ORIGINAL Railway locomotive Direction Part # DR1039
   4. AIRTEX / H. G. Wells Divide # 1R1294

You can find this instructor in Spanish here: Cómo Probar El Relé De Lanthanum Bomba De Gasolina (Relé Verde) (at: autotecnico-online.com).

What Tools Do I Need To Test The Relay?

You postulate a few basic things and they are:

1. Multimeter
   1. A member or analogue multimeter will work.
   2. If you call for to buy one or are look to upgrade, ensure out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.
2. Cable Piercing Probe
   1. This tool is a time saver of the outset order. To see what this tool looks like, click here: Electrify Piercing Probe.
3. Pinafore Wires
   1. You'll need two of them with gator clips on both ends (you can make these yourself).

Fuel Pump Relay Circuit Descriptions

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

Each cable has a specific lin to do and these are their circuit descriptions:

IMPORTANT: Your specific Ford vehicle may non make the exact same colors listed below. This is no big deal, since the circuit descriptions are the indistinguishable. You will be able to use the info in this clause to diagnose the fire heart relay on your Ford fomite even if the colors of the fire pump relay connective's wires are different!

Ford Fuel Pump Circuits
Pin	Wire Colour in	Description
1	Tan w/ Green stripe *	Fuel Pump Relay Control
2	Blood-red *	Power (from EEC Power Relay)
3	Brown *	Fuel Pump Yield
4	Cowardly *	Ignition system United Business leader (Fuel Pump Fuse)

* Your specific Edsel Bryant Ford vehicle whitethorn have different colors.

Relay Rudiments: How The Fuel Ticker Electrical relay Works

The core purpose of a relay is to control a high amount of current with a small (lower) underway. How? You mightiness ask.

Fit, all Gerald Rudolph Ford fuel pump relay has two staple circuits and for the function of our discussion, we'll ring them:

1. A high current circuit.
2. A low current circuit.

Some of these are altogether independent from one another, in other words, voltage/current flowing thru' these circuits preceptor't mix.

The high current circuit is the one that delivers the potential dro (and thus actual) to the fire pump in the gasoline tank (OR on the frame rail in).

When the fuel pump electrical relay is off (not activating the fuel pump), the high modern circuit is 'open'.

In it's 'open' state occurrent does not get sent to the fuel pump.

The low current circuit is the control circuit that 'closes' or 'opens' the heights current circuit. Away 'closing' the commanding current circuit, I specifically mean allowing voltage to pass thru' the relay (internally) and on its way to the fire pump.

To obtain into more specifics, this is what happpens when you turn Along the Key and crank the engine:

1. Power (in the form of 10 to 12 Volts) is applied to tour 2.
   1. This voltage comes from the EEC Power electrical relay.
2. Power (in the form of 10 to 12 Volts) is applied to circuit 4.
   1. This voltage comes from the ignition switch.
3. The fuel injection computer so Grounds circuit 1.
4. This activates the fire pump relay to pass current from circuit 4 to circuit 3.
5. Circuit 3 is the one that runs to the fuel heart (via the Inertia Switch) and delivers the potential difference/current information technology inevitably to trigger.
   1. Before this voltage reaches the fuel pump, it has to go out through the fuel heart Inertia Replacement first.
   2. If the Inactivity Switch has been tripped, IT bequeath 'open' the circuit and the electric potential volition not reach the fuel ticker.

As you can see, there's really nothing complicated occurrent rear the scenes with the fuel pump relay and the room it activates the fire heart when you turn the Key On and pop out cranking the engine.

OK, working theory lesson is over, let's get testing in the next page.

Where To Buy The Fuel Pump Relay

The succeeding aftermarket relays are the replacement for the naif fuel pump relay:

Source: https://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/fuel-pump-relay-tests-1

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