2003 expedition fx4 electrical problem

[Mwest]

The fuel pump relay inside the fuse box went bad. I switched it with the matching one from the trailer lights and reverse lights. Truck ran great for about 5 miles. Then the check charging system light, abs light, and advance trac light came on one by one and all other electrical components starting shutting off one by one. The truck kept running for another mile then died. I thought it was the battery so I charged it. Now the battery says 12 volts but the truck still won't start. I can hear a buzzing and clicking noise coming from the fuse box. No power to anything though. Any help is greatly appreciated!

 

[FordandPolaris]

It sounds to me like the fuel pump itself may have gone bad as well... What makes you think the relay went bad?

 

[Mwest]

I pulled the fuse panel that's in the passenger compartment, disassembled it and found, relay 303,melted.

 

[VTfireftr]

The relay melted because the fuel pump was drawing too much power through it before it failed.

Relays are rated like fuses. They can only "flow" a limited number of amps before filing. You are very lucky you only melted the relay and didn't start a fire in the electrical panel and lose more.

 

[ELVATO]

New fuse box.

Sounds similar enough to this -> http://www.expeditionforum.com/f16/expy-wont-crank-buzzing-sound-3436/

In my case, the actual PCM relay melted. Seems both R203 and R303 have the PCM in common. Poor design in the early 03 models. New fuse box with redesigned circuitry solved my issue.

 

[Mwest]

Do the dealerships have the updated units?

 

[ELVATO]

Yea I'd imagine so. This was supposed to be a problem with the early 03s. Either way, the part number of what I got is in the thread. Just make sure you don't get the same part number as what you currently have haha.