This van intermittently began running badly and started poorly. After a couple of weeks it stopped running at all. I checked relay, fuses etc. they were fine.
I could not find a rollover switch anywhere and neither the manual nor online solved the question if this model had one at all.

Anyway I have just pulled the tank and it turns out the pump runs fine with 12v applied to the leads. A voltmeter measures an erratic ~3 volts on the harness that snaps into the fuel pump when the key is on and if I measure the positive lead to a good ground I get about a consistent 11V. So this leads to the following questions.

1 Is the pump activated by straight DC or is it PWM or some other signal?

2 Am I correct in assuming there should be a reliable ground on the appropriate lead and that this should not be switched (it is after all going into a tank full of flammable liquid)?

3 If there is any switching, such as a rollover switch, would it be on the relay activation circuit - in which case I don't need to investigate that since the relay activated and was swapped with another...

I am suspecting corrosion in the wiring harness as my problem particularly a bolted coupler next to the driver side exhaust manifold positioned in a way to invite road salt (something they do in NY, for you southerners) into some of the lead entries.

If anyone has a schematic of the circuit I would appreciate it. I don't know if there are additional mappings for the various harness routings and connectors.

Jma

 

It's PWM.
Look under the rear of the vehicle for a Fuel Pump Driver Module. Known to have corrosion problems between module and frame member. PCM sends signal to FPDM which sends signal to pump assy.

 

Would that be a 1X2X2.5 inch box with a half dozen wires going in with no obvious purpose next to the spare tire?

 

After all of that it turns out to be rust on the ground lug at the pump driver module.

Now the next problem is the plastic retaining clip on the fuel line is broken. The auto parts store said to try the dealer. The ford dealer says it is not sold separate but incorporated into the fuel line. Is there anywhere to obtain these or a reliable way to fasten the fuel line. I'd prefer to have the right part rather than make a fork of metal to shove in the groove and tape it to hold it in place

 

Glad you found the problem.
If you cannot get what you need from auto supply stores or dealer, you might try a salvage yard.

 

All back together and fuel pump control module ground wire cleaned... I had not quite found the problem.

It turns out the frame is not grounded. If I take single jumper cable and run it from the frame to the body it works fine. It is a little soggy out so rather than crawl around and look for it, I will ask if anyone knows where the 'official ground' is fastened to the frame?

Hopefully this will serve as an aid if someone has the same problem.

Also a footnote regarding the broken fuel line retaining clips: I was able to bind the fuel line coupler to the pipe with wire as those retaining clips seemed to be un-obtainable. The seals are internal and work fine. Of course this must be done in a very reliable way.

 

Due to the importance of good grounding , manufacturers may have a few grounds. Usually there is one from the battery negative terminal that goes to the front of the vehicle in the radiator area. You can't have too many good grounds. There is usually a separate ground for the fuel pump module and I would suspect that is the one that is defective. There are several things that rely on a chassis ground , so if you can just run one any place that is convenient and if possible look at all the grounds you can see and clean them, make sure they are tight and apply some dielectric grease to them to help prevent any further corrosion.

The negative battery cable is connected to the engine and then a wire is run from the engine to the firewall and sometimes to the chassis.

 

Well that was too long a journey for a small problem. Just for the record, the grounding strap between the body and the frame was under the door post between the passenger & side cargo doors.

Problem solved, thanks for the suggestions, they lead to finding the problem.