Solved Fuel pump power issues after transmission swap.

[Tshaw88]

Hello everyone I have spent a good amount of time the last month swapping the 5r55s from my donor 2002 explorer into my 2005 explorer. The swap is done however when I attempted to start up the car I was met with a new problem, I had no fuel. I've spent the last couple of days attempting to figure this out and I am stumped. I have check both fuel pump fuses and both work as they should, I have swapped the relay with a known working relay, I have used a jumper on relay pins 3 and 5, when using a jumper I get 12.6v at the inertia switch and the pump kicks on, when I put the relay in I get no voltage at the switch and no fuel. The 15amp fuse that is supposed to trigger the relay is fine, it shows voltage at the fuse but for some reason the relay does not seem to do it's thing. Any thoughts would be greatly appreciated.

 

[BrooklynBay]

Do you see the check engine light turn on when you turn the key? The computer controls the pump. The pump won't turn on if the computer doesn't turn on.

 

[Tshaw88]

Yea all of the dash indicator lights are working and functioning. As well as the gauges. I was thinking pcm as well for a while

 

[BrooklynBay]

Check the power & ground wiring for the computer.

 

[Tshaw88]

I talked to my cousin this morning about that, he's a Ford Sr. Master mechanic in upstate NY, I'm out in Rhode island, he managed to pull up a wiring schematic for me and discovered the pcm talks directly with the fuel pump driver module not with the relay, the keyswitch is what activates the relay. So I did some more digging around and discovered the pin 5 connector inside the fuse box had opened up just enough so pin 5 on the relay was not making contact. I pinched the connector closed with a screwdriver and she fired right up. Always the little things isn't it? Lol

 

[BrooklynBay]

Thanks for the update. Your thread is now marked as solved.