we have a 2003 suburban that has had fuel pump problems for years. two years ago after towing a boat down a steep windy mountain the pump quit on us. with no power breaks or steering and thousands of lbs of trailer pushing us down this mountain it could have ended fatally, we got it stopped, punched the tank out of frustration and it started back up. we got home, dropped the tank, changed the pump and it ran great. yesterday my brother was driving it home from work, he turned a corner and the car just shut off. turn the key, no hum from the pump, so we dropped the tank again and replaced the pump and connector from the square one to the flat one. when we checked to see if there was power going to the pump, there was not. all fuses are good, all relays are good, brand new pump and connector triple checked and wired up right. i guess im just baffled and have reached the extent of my knowledge on this subject. is there some kind of sensor some where that could cause this whole circuit to go cold? the wiring schematic shows the relay wires tracing back into the PCM, from the PCM comes the fuel pump relay and the fuel gauge (also now not working) could i have a bad PCM/ECM? i dono, i dont really want to chase wires but if i have to i will. what might cause this circuit to go cold on a turn? oh ya, ran codes, only one was a evap pressure code. that one weve had on and off for a while, maybe has something to do with it, but hasnt effected it in the past.

 

Welcome to the forum.

Were the new pumps AC Delco?

 

I assume you are checking for power at the connector? Is the relay energizing at all with key on? Genericlly speaking (I don't have anything on your model) key on, conditions ok to start, relay will energize, closing contacts from a seperate fused circuit to the pump.

 

I'd make sure the fuel pump fuse is good, and as kevinkpk pointed out, check that the relay is working, I think it can be swapped with one of the others in the fuse box of similar size....
And of course make sure you are turning the key all the way on...