Im installing an inline walbro 255lph and made my own harness with a relay but can not figure out which wire I should be tapping into, I have the fuse box loose but cannot really see what wires go up into the factory fuel pump relay, I have been searching for an hour and cannot find any info, please help!

 

its the grey wire in the big bundle of wires under the fuse box that goes to back of truck

 

Thanks, actually as soon as I posted this i re-worded my search and found it,, grey wire in one of the wiring harnesses coming out of the fuse box just like you said. shows 12v when factory pump kicks on.

 

the fuel pump trigger is actually this one

 

I found that pic first, but the wires in the bottom of my fusebox were arranged differently and were very hard to reach without dismantling some of the wiring so I ended up finding other threads saying it's the grey wire coming out of the harness and it seems to be working fine, shows 12v only when the fuel pump kicks on.

 

That's the wire going to the fuel pump, but the actual trigger wire for the relay is the green and white one

 

I see, But will there be any problem using the grey wire like I did? I found others who used it, but I havent put the pump in yet to test, just working on the wiring

 

no, it will work fine, but if the fuel pump relay fails it wont have power

 

ok what your saying is if my factory pump relay fails then my walbro relay wont get any trigger signal and neither pump will turn on, correct?

 

correct. OEM relays are pretty reliable so I wouldnt worry about it.