Question about 1990 Mercury Grand Marquis

1 Answer

Fuel pump relay location on a 1990 mercury grand marquis.

My car wasnt recieving any fuel to the engine so i replaced the fuel pump. i tested for power going to the fuel pump and my meter showed no power. i was told to replace the fuel pump relay. i just dont know the location of it. if you have any other suggestions on what could be wrong please tell me.

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 303 Answers

Check the fuse .if the fuel pump was bad you blew the fuse . there is a inertia switch in the trunk or under the dash you could check . push the red button to reset relay should be under the hood in the fuse box check your book if you have one.

Posted on Nov 19, 2008


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I have a 97 sebring that wont turn over. I sprayed starter fluid in the intake and it turned over, so i changed the fuel pump, the fuel filter, and the relay. What else could it be?

Is the PCM - engine computer energizing the fuel pump relay ? The best place to test the fuel pump electrical circuit is at the relay , using a test light or volt meter were the relay plugs into. On the bottom of the relay there should be numbers 30,87 an 85 an 86 . 87 an 30 are the fuel pump side of the relay . 85 an 86 are the control or turn on side of the relay . Two of the pins should have B+ voltage . One will be open an the other will show ohms resistance on ohm meter . Find a wiring diagram at an test for power an control of the relay . Test don't guess an don't be a parts changer , Fuel Pump Electrical Circuits Description and Operation

Jan 26, 2016 | Cars & Trucks

1 Answer

My new fuel pump only primes when wired direct?

Well you need to get out the DVOM - digital volt ohm meter an check for battery voltage at the fuel pump relay ! if you replaced it you saw the holes it plugs into in the relay / fuse box ? Put you volt meter on the 20 volt scale , hook the black lead to the battery negative or a good engine ground an take the red lead an touch - don't stick it in an spread the terminals . Two of the holes should have battery voltage ,if not check the EEC power relay ! If you find voltage at two holes change the meter to ohms , leave the black connector on a good ground an touch the red to the two holes left , one should be open or OL on the meter , this is the control side from the engine computer . the last hole should show a few ohms resistance , this is down through the wiring to an through the fuel pump to ground . You have two different wiring circuits , control an load side , load side being power to the fuel pump an control side is power an the engine computer supplying a ground energizing the relay closing the contacts in the relay sending battery voltage to the fuel pump. Test don't guess !

May 25, 2015 | 1987 Ford Ranger

1 Answer

Where is the fuel pump relay

It should be in the fuse box

Nov 25, 2014 | 1990 Mercury Grand Marquis

1 Answer

Engine starts then dies after 2 to five minutes 85 mercury grand marquis have replaced distributor , ignition module , coil

Since you have replaced some of the ignition parts, have you checked fuel pressure and the fuel pump relay ?
Do you know what you are loosing when the engine dies ?

Aug 31, 2014 | 1985 Mercury Grand Marquis

2 Answers

1990 Mazda Miata will crank but not start. Just replaced battery, spark plugs, and air filter. I used some starting fluid in the air intake and the engine started so I believe its a fuel problem. I tried...

Not sure what you are using as a ground when checking voltage. If you check at the connector you should have 12 volts at the blue wire with the red stripe (red prong on volt meter) and you can check putting the ground/black prong on your volt meter on either one of the black wires on the connector. When turning the key just to the on position you\'re only going to get full power for about 2 seconds unless you\'re turning the engine over. If you\'re not getting full voltage try putting the black prong (leaving the red one from meter on the terminal that has the blue wire with the red stripe) using a good ground on the body of the vehicle (the black prong from meter). Now if you\'re getting the voltage you need then you need to trace the black wire(s) to where they are grounded out on the vehicle and clean/tighten and repair the ground as well as making sure you are getting zero continuity from where the ground is on the body to the connector at the fuel pump. A bad ground will cause weak power. These are also the 2 wires you need to apply direct power (on the pump side of the connector) in order to check the pump as you asked. Since there are 2 black wires at the connector, if you have direct power to the blue and red wire and put your ground on one of the black wires and it doesn\'t run, than try using the other black wire (or where it would be on the terminal of the connector...pump side) at the connector because that would mean you are testing the wrong ground wire for the pump itself. If your ground is good down there and it turns on when applying direct power than it could be a number of things but the 2 most common would be the fuel pump relay or the air flow meter/sensor. Start with check power and ground and direct powerfirst. If the pump is working when putting direct power and your grounds are good then further testing needs to be done of course. I\'ll be happy to help you with further testing if needed like checking the relay and/or air flow meter. You will need an ohm meter for further testing. I hope I was detailed enough for you to understand the testing needed at this point and I hope I was able to help

Oct 12, 2013 | Cars & Trucks

1 Answer

1994 Lincoln Town Car Fuel Pump Failure?

Test the electrical circuit ,voltage drop ! Do you know how do to automotive electrical testing using a DMM - digital multi-meter ? Looking at a wiring diagram so you know what wire's are what ?
Free wiring diagram's here
Enter vehicle info. year , make , model an engine size . Under system click on engine , then under subsystem click on fuel controls . Click the search button then click the blue link .

Testing Electric Fuel Pump Problems with Voltage Drop Test

How to Test for Fuel Pump Voltage Drop

Trouble Shooting Fuel Pumps Voltage Drop Test Part 2 Expanded In Depth

Fuel Pump Electrical Circuits Description and Operation

Nov 06, 2017 | Lincoln Town Car Cars & Trucks

1 Answer

How to test a fuel pump relay in a 1999 toyota tacoma

Most relays have a diagram on the side showing the terminals by number.
You would take a test light or meter and check the terminals in the fuse box for power and ground. You should have two power wires, one ground from the computer, and the circuit to the pump. Keep in mind the computer grounds the relay for only 3 seconds if the engine does not start.

Sep 15, 2012 | 1999 Toyota Tacoma PreRunner

2 Answers

Replaced fuel tank and pump and now car won't start.

no engine stated.
details are based on that..
so is it still the old pump there,
this is very simple
using a volt meter. (the pump has 2 wires, measure across those)
back probe that connector to the pump. 2 pins.

12vdc cranked, if you have 12vdc cranked
but fuel pressure is 0 the pump is gone
no pump runs on 0v, or 6v, its 12vdc there,
i can not understand those fues tests
if the voltage fails to the pump it can be
the power wire or ground wire failing .
do all tests connected, or the readings will be useless.
connected is live testing, under full real conditions
and win. every time.
if ground is tested and rises to 12vdc cranked, ground is bad.
only Ohms laws here,a simple equation.

not sure why your float fails. my guess its bad.
and easy test using ohms, disconnected.
that is another problem.

ill look at your fuse, pretend V6 engine.

the service manual shows
f10 fuse is fuel pump
12vdc both side cranking is a GOOD FUSE.
note all words above.
F10 gets all power from pump relay,
so if you dont crank the relay can be off line
an F10 will be dead.
(the schematic is clear)

here is a facts on all cars, next (pure software in PCM )
  1. pump only runs 3 seconds key on, ,
  2. pump never runs, if not cranked.
  3. run cranked and all run if engine stays running.

see? and varies by year, engine, and even ECU upgrades
so a SAVVY mech always cranks to do tests.
that means its a 2 man job. sorry but that is a reality of working any car until you learn what yours does.
warning have a care here that changes rule 1 to 2, below 20F out door temps, (fun no?)

crank and measure like this.
the pump has 2 wires, red hot, black ground
meter across, pins 1 to2, red back is 12vdc cranked
meter black tests lead (volts) to body perfect metal ground
and meter red lead to pin1 red shows, 12vdc cranked
12vdc means 10 to 12vdc cranked, (battery does that)
then move red test lead to pin 2, black
cranked, 0v, if see 1 volt or ore the ground called.B26 is bad.
if the pump has 12vdc on it, you hear it,
do not run it dry its fuel cooled and fuel lubricated or you wreck it.
if it is heard to run you then see fuel spec fuel pressures.
or its bad. (30psi?)



Mar 13, 2017 | 1998 Isuzu Trooper

Not finding what you are looking for?
1990 Mercury Grand Marquis Logo

1,295 people viewed this question

Ask a Question

Usually answered in minutes!

Top Mercury Experts


Level 3 Expert

78267 Answers


Level 3 Expert

5653 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers

Are you a Mercury Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides