QuestionQUESTION: i know you said 2000 and up,but 99 merc grand marquis,would not start,just grind.finnaly started when i heard fuel pump cut on. ran for a while to charge battery. after i stopped and cut it off, no fuel pump comes on now what can i check that cuts on fuel pump.
ANSWER: This is some what a common concern. Do you have the owners manual ?? If so, in the index, look up fuses.. There you will find a picture and description of the fuses and relays under the hood in the battery junction box. Switch the relay ( black square looking fuse ) from the a/c to the spot where the fuel pump relay is, just for testing purposes and see if this changes things. If it does buy a new relay, about 3-4 dollars and replace it. Fuel pumps are known to go bad on these vehicles but, usually once they stop, they stop. Try this and get back to me..
If you don't have the ownners manual, you can google, battery junction box for 99 grand marquis
-b-
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QUESTION: distribution box under hood, says #1 fuelpump relay/fuse 20 amp the square blocks say rear defrost relay , there is 4 of them nothing about fuel relay
ANSWER: rechecked wiring diagram and your correct, they changed it in that year at this point being that the fuel pump is cotrolled by the on board computer. the next time it doesnt start, after cranking it over. open the hood. fid the fuel lines. of of them should have a cap on it like a bike tire valve stem. unscrew this cap and insert a pen into the tip of the schraeder valve. fuel should shoot out. if it only dribbles out, very good chance your pump is bad. second option is after it not starting, turn key to the on position and take a rubber mallet and tap on the bottom of the fuel tank, this should jar the pump free.
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QUESTION: there is a box like thing on bottom of fuel tank,with wires going to it. what is it? thanks alot
Answeri've looked over the diagram a hundred times and can't find any box that should be attached to the tank.... except the fuel pump driver module but, that should be located in the trunk on the left hand side, small black box, rectangle shaped connector with 4-5 wires going to it.
