I lost power to my lift pump

[JGaede]

I have a 2004. 5 HO, 4x4, auto trans. I recently replaced my batteries and afterwards now I'm not getting power to my lift pump. I pulled the lift pump off which is still located on the fuel bowl and tested it with power straight from the battery and it works fine. When I cycle the key and bump the starter I get no voltage to the lift pump. I've checked all the fuses and relays under the hood. I have no codes either. The dealer can get it in until late next week. Does anybody know what would cause this and what I need to do to fix it?



Thank you

 

[TCDiesel]

It may be the ignition switch. No power to the Pump Immediately after the Battery Change?

 

[JGaede]

Nothing to the pump at all but it will crank over

 

[JGaede]

Everything works as far as the radio,all warning lights on the cluster the engine cranks, but no power to the lift pump with the ignition on or while cranking the engine over. There are no trouble codes either.

 

[TCDiesel]

You won't get codes ,the circuit is not on PCI, Send email address to -- email address removed -- . I will forward the wiring spec's. the ECM controls the On/Off, but it is powered by the ignition switch, with the spec you can check the (Pins) on the ECM Inputs and outputs.

 

[JGaede]

ok this is what i found. I got under the dash this morning and found an old alarm with no control module there still hooked up (from a previous owner). I have no clue as of the make or anthing but I think when I changed the batteries it activated a kill switch that most alarms have when they lose power. I have removed this from the truck already is there any way to reset the computers without a dbr tool to deactivate the alarm kill to the computer

 

[TCDiesel]

I will make you a harness to by bypass the ECM with a fusible link.

 

[Missouri Mule]

Sometimes there is a reset button under the Steering column.