Okay all fuses and the relay are good, fuel pump is a brand new Bosch 040. The fuel pump does not come on. No fuel comes out the schraeder valve on the crossover fuel rail. Is there anything other than the fuses or relay that can keep the pump from running. BTW the truck had been sitting for a month or two till I got the tranny in.

 

Are you sure the pump module is plugged in correctly? If the problem started immediately after you swapped the pump I'd look at the possibility that something was either not plugged in or came unplugged during installation.

 

Is this a intank or inline??

John

 

in tank but it started before the swap. it started when my truck was down for a another transmission and it just set there. I replaced the transmission, third one in the past 4 months, and this time it just cranks and builds no fuel

 

If the pump doesn't run at all, then there is a wiring issue. Start at the front and work your way back. If the relay clicks, then move to the next piece in line. If the fuses are good, move to the next. Check the voltage at the connectors for the fuel pump. You will find the problem somewhere along the way. If the connector on top of the tank has voltage, it's time to pull the tank and check the connections inside the tank. Start from the top and work your way down and you'll find it.

 

Thats just it, I dont think that its in the wiring at all, I dont believe the relay is getting power to it, I just dont know which prong to check for the voltage into the relay. Is it possible for something before that to be affecting it, like maybe the security system or ECM or something like that?

 

Get the multi meters out, turn the truck on and start poking... On the wires to and from that relay

John

 

Look on the bottom of the fuel pump relay. You will see markings for pins 35, 85, 86, and 87. Match the pins on the relay to their respective slots in the fuse box. Either pin 85 or 86 will be the trigger, and the other will be a ground. Probe the slots for pins 85 and 86 to check if one of those two switches voltage when the fuel pump is supposed to be on. (small paperclips straightened and pushed into the slots work well if your multimeter probe will not go in). If there is no switched voltage on either of these, there's a problem in the trigger wire.

If that works ok, probe the slot for pins 35 and 87. One of these should be a constant +12V from the battery. If one is constant hot, try to jumper the slots for pins 35 and 87 together. This should kick the fuel pump on. If this doesn't work, the problem is further back.

If there is no constant voltage on either of the slots for pins 35 or 87, check the fuel pump fuses again. Best to use a continuity tester to make sure the fuse is good. I had a fuse once that did not look open, but when I put the continuity tester on it, it said the circuit was open.

This will give you a direction to head with troubleshooting.

 

I would also check polarity to the pump...

 

thanks this is some info i needed since i have no wiring diagram, and i did check resistance on all the fuses so thats not it. Polarity on the pump is not the problem i am pretty sure of that, the old pump works still. Also black is the ground, grey is hot.