2004 Lincoln Navigator - Crank - No Start Possible non-serviceable fuel relay or fuel pump

[driller]

When you test for voltage on the DG/YW wire, is it still connected to the wiring to the fuel pump?

My thought is to disconnect the fuel pump and test the voltage at the DG/YW wire both at the CJB and inertia switch. I only say this in a generic way as many voltage or resistance checks in typical diagnostic subroutines specify the circuit being tested to be disconnected at a harness connection.

 

[tedallen]

@driller I did have the connector unplugged at the inertia switch when checking voltage at both the CJB and inertia switch.

 

[tedallen]

@Action and @driller I verified all of the fuses (and moved over additional ones I needed) in the CJB I got from Pull-A-Part yesterday and the behavior changed. I do see12v briefly on the DG/YW wire at both the connector and at the inertia switch connector. It definitely isn’t for 2-3 seconds. However, when cranking the engine I am now seeing 12v while cranking at both locations, but the pump does not appear to run. I know @Action mentioned the possibility of the PCM controlling the ground signal to the pump. If that is true for my vehicle, I don’t know where to test to see if that ground is being completed by the PCM. I guess the next thing I am going to do is see if I can gain access to a connector going to the file pump that includes the power coming through the inertia switch as well as a ground to see if I can determine anything there.

 

[tedallen]

I couldn't see a way to access the fuel pump connector without lowering the tank, so at this point I'm going to try to remove it completely and replace the fuel pump and check wiring to it with the tank out of the way. The service manual says to remove the straps, lower the front of the tank about 1" and then remove the rear driveshaft. Is it really necessary to remove the driveshaft? I saw a guy doing a fuel pump replacement on a 2003 Navigator and he didn't remove the driveshaft. I haven't been able to get the rear strap unhooked from the slot because there isn't a lot of room to rotate it between the tank body and the driveshaft. Maybe that is at least one reason why the service manual says to remove the driveshaft. I think the guy in the video just bent the straps down instead of removing them (at least until the tank had been lowered a good bit.

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[G-734110]

@Action and @driller I soldered a new relay on the CJB PCB and the results are the same. I am atill only seeing 6v on the DG/ YW wire both at the CJB connector and the inertia switch connector. I’m headed to Pull-a-Part to see if I can get one that matches the part number before they close.

Did the new fuse box work