View Full Version : 90 SC Blowing Fuel Pump Motor Fuse

04-02-2003, 11:42 PM
when i got in my sc to go some where today i let my windows down then started to crank it when i smelled a burning smell(Like Wires)The Car Turned Over But Would Not Crank So I Got Out Checked The Fuse Box Under The Dash All The Fuses Were Ok Poped The Hood And Checked The Fuse Box To Find The Fuel Pump Motor Fuse Was Blown So I Replaced It Got Back In My Car Tried It Again And The Same Thing Happened.Crazy Thing Tried To Let The Power Windows Back Up And They Did Not Work(Keep In Mind The Fuse Is Not Blown And I Dbl Checked With A Known Good One)Every Thing Else Works Fine.:confused: Any Help Would Be Greatly Appriciated.......I Allready Replaced The Fuel Pump Silenoid(Did Not Help)The Car Was Running Fine Before Today Except For A Idle Problem When TYhe Heater Or AC Is On.Figure That Probly Is Plugs And/Or Wires.

04-03-2003, 12:55 AM
This is a tough one because the windows and the pump are on two separtate circuits.

Let me get this straight,

All the fuses are good now,
the fuel pump relay is new,
everything works normally (including headlights) except the windows won't go up and it won't start presumibly because the fuel pump isn't running.

Now, with everything off and quite, turn the key on and off while listening for the fuel pump, can you hear it run?

Check the inertia switch located on the left trunk wall, push the red button down.

Locate the EEC test connector on the rear of the pass side fender under the hood. It will be pushed into a black protective cap that is labeled as such. remove the large connector and jumper the two terminals farthest apart, or on each side. This will manually activate the fuel pump if it has battery power and it works. While these two terminals are jumped you should be able to hear the pump run, especially with your ear up to the filler pipe (cap off).

Check the battery and it's termial connections well.

Examine the wires connected to the battery hot side of the starter relay. Look for a melted insulator or soft wire that will strech. Look at the connection nuts, make sure they are tight.

Look down on the bottom of the power distribution box. You may have to get it pulled up, removing the battery will help you see how to do this as would removing the washer reservoir. examine the wiring and connectors associated with the power distribution box.

In any case I think your pump is burned up, that's usually the only reason you'll blow a fuse. But with the burning smell and other electrical problem all the power supply and ground circuits (connections and wires) need to be examined thouroughly first.

Let me know if you find anything unusual.

04-03-2003, 12:59 AM
Ignition switch.


04-03-2003, 01:09 AM
Go with what Jeff says, he's got the crystal ball. - LOL

Seriously, that's the connection that I was missing and keeping me thinking so long. Jeff is one of my best buds and he knows electronics, I would check the ignition switch first.


04-03-2003, 01:20 AM
I remember there is a recall on that switch. You probably need to check with the dealer to see if it has been changed, chances are it hasn't. That plus the burning smell makes me think that's what it is. Make sure of what works and what doesn't then get back to us.


04-03-2003, 01:47 PM
every thing works on the car except the power windows the 30Amp Fuse For The Fuel Pump Motor Blows Every Time I Start Turning The Car Over.I Tried A 40Amp Fuse(Only Because I Ran Out Of 30 Amp Fuses) And It Did Not Blow But Got Glowing Red Hot And The Car Still Did Not Start.Will Check On THe Ignition Switch With Ford(Will Reply On That Tonight)The Fuel Pump Apears To Be Running When I Switch The Car On Also.

04-03-2003, 07:56 PM
When you think about it the fuel pump is immersed in a highly explosive liquid and is an electric motor. Over riding the current limit when you know there could be a problem in there isn't such a bright idea.


04-03-2003, 08:55 PM
The Wire Going To The Key Switch I Think It Is The Key Warning Buzzer Is Broken Would That Matter?have the electronic ignition switch(Not The Key Switch)Just Have To Get The Old Screws Out To Install It.i realize that putting in 40Amp Fuse Where The 30 Amp Fuse Was Not The Smartest Thing In The World But I Only Did That Because It Was Late And I Had Just Installed The Fuel Pump Motor Relay And Wonted To Test It.

04-04-2003, 12:14 AM
Have you done any work under the car? Do you have a multi meter? You might have 2 different problems. Give us some history on this problem like what has happened in the past.


04-04-2003, 06:21 AM
If the fuse blows with the proper fuse and doesn't with a bigger fuse (that get's warm under load), then what it's FEEDING is drawing too much current. That's what needs to be replaced. I think the windows may be a separate issue.

BTW: The ignition switch recall I seem to remember (it was 12 years ago) was for a "potential short". Ford replaced mine then.


04-04-2003, 02:21 PM
I Just Bought The Car In Febuary,2003 I Have A Multi Meter.i really need to get the windows up its suposed to rain tomorrow and the car is outside.This Is The First Thing That Went Wrong With The Car Since I Bought It It Has Aprox.122,000 Miles On It And From The Records That Was With The Car It Seemed To Be Well Maintained Allthough They Go Back Aways And Are Not Current.

Duffy Floyd
04-04-2003, 08:04 PM
Minor point.....liquid gasoline is NOT explosive. Gasoline VAPOR is explosive but only under a relatively minor range of O2 content. Inside a gas tank it is HIGHLY unlikely that the concentration of gasoline vapor to air would ever reach the explosive point.

04-04-2003, 08:34 PM
J57ltr <<<------You The Man............. Ignition Switch Installed Car Crunk Up.Still No Power Windows Though About A Month Ago I Had To Replace The Gears In Both Window Motors,It Was Pretty Cut And Dry Installing Them,Much Easier Than The Ones I Have Replaced In My F-150 Or The 35Aniversary Camaro I Had.And There Has Been No Sign Of A Problem With Them Till Now.Checked The Under Dash Fuse Box Replaced The Fuse With The Fuse From The Power Seats(That I Know Is Good Because The Power Seats Work)And Still Nothing.Still Seems Strange That The Windows And The Ignition Problem Occured At The Same Time And Makes Me Think There Related Somehow.But I Dont Know............. If There Is Any One That Can Help Please Its Going To Rain For The Next Three Days And All I Have Is Some Plastic To Cover The Holes With.

04-05-2003, 02:39 AM
I don't have access to a good schem for the chassis. Try to roll up or down the pass side window from the pass side switch in the off chance that both switches failed on the drivers side. I'm going ot look in the Chitlin and see what I see. Glad I could help.


edit: remove the dr side switch panel and see if you have power on the big fat wire (don't remember the color [red?]). it's a phillips screw then slide the panel the the front.

There should be a 20 amp breaker, there is a Red/lt blue feeding that circuit. check the connection it the fuse block where this breaker is located. The seats and locks are on 1 circuit and the windows are on their own. Use your multi meter, check for 12V at the fuse box at the breaker terminals. it might be charred or something.

Duffy Floyd
04-05-2003, 03:28 AM
I did some internet research to find the flammability limits for gasoline. Here they are:

The Lower Limit is 1.4% by volume in air. Below this value no ignition.

The upper limit is 7.6% by volume in air. Above this limit no ignition occurs.

This illustrates why when you install an aftermarket fuel pump exposed electrical terminations are no big deal. Gasoline is not very conductive and even if there was a spark in all likelyhood the pump is submerged in gasoline...if not the concentration of gasoline vapor in the tank is toi be expected to be above the magic 7.6% limit.

04-05-2003, 03:56 AM
It's probably not likely, but there is always a chance that something out of the norm could happen.

(Wasn’t on my SC) One night after driving my car aggressively I drove home and parked it and went inside the house. The next day I went to work and when I came home for lunch as I got about half way across the street I could smell gas. That struck me as odd since no cars had passed and it was obviously fresh. So I thought to myself well it must be my car. I walked around back and found a nice puddle under the tank. I looked under to see what it was and found it was coming from the top of the tank, which was 3/4 full.

Well now I have a huge puddle and gas still leaking from the tank. I was unsure what to do. It wasn't leaking that morning (about 45 deg) and by afternoon it was up to about 70. I went out to the car and opened the cap because I was going to drain about 3 gallons out to see if it would stop until I got home at 5. When I opened the cap it was under quite a bit of pressure. I found the purge line to the charcoal canister was plugged. When the temp rose in the afternoon the change in pressure in the tank caused the gas to be pushed out of the tube and out of the cracked line.

Suppose that things went a little different, say a fuel line gets a small hole in it and you park your car after driving it around. The gas temp is higher than ambient because it's been circulating through the fuel rail and has picked up a little heat (so it's maybe 1 deg higher than outside) you park the car and over night the temp falls and the tank cools and draws in nice fresh air. When you start the car in the morning your fuel pump connection lacks something to be desired and gets hot enough to cause ignition.

Like I said earlier it's unlikely but if the right (or wrong) things happen it could become hazardous.


04-05-2003, 02:07 PM
Passanger Side Window Does Not Work Either(From Either Switch Drivers Or Passanger).I Droped The Fuse Box And Inspected The Wires And None Showed Any Signs Of Overheating.Pulled The Driverside Door Panel Inspected The Wiring There Again No Sign Of Overheated Wires.Is There a Way I Can Bypass The Switch To See If The Motors Are Working?

04-05-2003, 02:58 PM
Pull the switch and run long jumper wires from the battery to the window motor leads. One way is up the other is down.


04-05-2003, 04:30 PM
Brief Update-Checked The Volts At The Breaker In The Fuse Box It Was 20 Volts Checked The Volts At The Switch 0 Volts,The Trunk Switch Does Not Work Either Pulled Fuse Box Inspected Wires On Back And All The Wires Under Dash I Could See all apeared ok

04-05-2003, 06:00 PM
Primary junction block is the only place the windows and trunk release connect, its located under dash.. left side terminal 12

04-06-2003, 02:19 PM
When I First Installed The New Ignition Switch The Car Crunk And I Drove It About 5 MIles Turned It Off For About 30 Min. Then Drove It A Couple More Miles Home.The Next Day I Started Trying To Diagnose The Power Window Problem I Had The Fuse Box Droped Ond Checked All The Wires Now The Problem With The Fuel Pump Motor Fuse Blowing Seems To Have Come Back.I Pulled The Codes And Got Two Codes.........16--Test Condition(R)(Whitch Is A Running Code For ---Rpm Too Low To Perform Oxygen Sensor/Fuel Test(5.0 Only)Whitch Probly Does Not Mean Nothing Since The Car Was Not Crunk And I Dont Have A 5.0.The Next Code Was 96--Test Condition(o)-KOEO&(C)Continuous Memory----PROBABLE CAUSE---Fuel Pump Circuit Open,Battery To ECA.