mustang5_0gt

the relay is located under the drivers seat right? its not under the hood on the passenger side that is on the fender

5.0liter_rice_eater

correct, fuel pump relay = under driver's seat, at least thats where it is on both my 86 and 90.

mustang5_0gt

ok thanks does anyone know if the relays go bad all the time or is it just one of those things

5.0liter_rice_eater

it occurs quite often, i replaced one in both of my stangs and i hear about people having to replace them as well.After you've chnaged it out once I don't think its a reoccuring problem, but i keep an extra one on hand just in case.

mustang5_0gt

i also want 2 mention i have no power to the red plug that plugs on 2 the top of the pump. SO the relay is probly bad i hope. I really want 2 fix this problem before the weekend or at least by friday

mustang5_0gt

ive never had 2 replace it in the 2 years that i owned it

5.0liter_rice_eater

actually, have you checked your inertia switch yet?

mustang5_0gt

ya i was looking at that how do u know if that has gone bad or what do udo with it

mustang5_0gt

what does the inertia switch do? i know its got a button thing on top that u can press down or pull up how do u know if it is bad. thanks

5.0liter_rice_eater

So you said you are getting power to the fuel pump relay connector under the seat, correct? Based on that fact and assuming the realy is good, this what you should try: First, check to make sure the red button on the top of the switch is depressed (just give it a push to make sure it isn't popped). If the switch hasn't been triggered or pressing the button didn't change anything then remove the connector going into the switch andplace a jumper acrossthe two wires to bypassthe switch.

EDIT: You can also jump the connector under the seat and bypass the fuel pump realy to rule it out.

The inertia switch was designed to "detect" a collision by messuring the cars inertia. The switch then cuts power to the fuel pump so you don't have gas pumping all over the place in a wreck.