Thanks for sharing the photos and details of your repair.

It's not serviceable for the typical shop or DIYer because the shop won't take the time (probably also lacks the expertise) to do component-level circuit board repair and DIYers are few and far between with the skills and equipment to do them. As it happens, you have both (as do I and a few other members here), but we're the exceptions.

For motivated DIYers who do not have the level of expertise you've exhibited, it's not at all difficult to simply splice a common Bosch-style relay into the external wiring to bypass the failed relay.

 

Appreciate the comment but don't feel I am that good, I have seen an excellent video of a guy diagnosing this problem with a volt meter and a pressure gauge. He hooks up to green / yellow wire on 4 pin connector, He contends that voltage drops first at the fuse box and then fuel pressure drops after. I found this reasonable. My vehicle usually did not throw codes but sometimes when it would die it would throw a lean code or 2 which is about useless. For the do it your self person with limited experience I believe taking an 8, 10, and 11 mm socket and a screwdriver to unhook the battery and remove the box to physically inspect the relay is not a huge stretch as long as pictures are taken for reassembly of the fuses and the metal clips on the board. The good thing is that Ford made all of the connectors different sizes. It should be remembered that each clip has a locking mechanism that must be released and the power lead has a removable cover that will need to be removed. If you are uncomfortable soldering relays maybe a trip to electronic repair or phone repair with the new relay might be reasonable. I was uncomfortable sending my board out to Ebay vendors in case it got lost and could not afford the new board. I have to admit when I put power back to the box it made me quite nervous. In my mind I could see smoke pouring out if I had screwed up.

 

It would, of course, have been far better if Ford had simply made the relays plug-ins instead of soldered in, then they'd have been easily serviced. However, that decision is long past.

 

Yep. Chased this problem on my Navigator with the DOHC engine.
Seems I was dropping around 1.5 volts between the alternator frame and the negative battery post. Narrowed it down to between the alternator frame and the engine block. I just made up a 4-gauge wire and ran it from the alternator frame to the engine block. Battery now reads 14.2 volts all day long (instead of 12.7 volts) and when its really cold here in Upstate NY it'll read 14.8 volts for a few minutes.


(And it really wakes up the ignition system. )

 

I replaced my fuse box and my charging system failed just like above and my alternator was not any problem before. Now its down to 8 + volts.

Jason did you replace your alternator and if so did it solve the problem?

Thanks Tony

 

I think the 20A relay Ford used for this circuit is barely adequate at best.
If I measured my circuit correctly the pump draws 15A.
Also, it is a motor so there is a higher tendency for arcing when the circuit is opened.
And for every time the car is started the pump is powered/turned off twice.
A higher capacity, easily serviced relay can be added fairly easily.
I mounted a 40A rated relay above the inertia switch next to the glove box.
The OEM relay output going to the inertia switch can be used to trigger the 40A relay.
The 40A relay output is then connected back to the inertia switch.
A new direct to battery feed line is needed for the 40A relay with a 20A fuse.
Now the OEM relay has .2A going thru the contacts instead of 15A.

 

You would think so but plug-ins have their own issues such as the socket contacts loosening up, generating heat, and then melting the relay. IMO, the best design is a separate pigtail with a relay socket on it. That way if the socket fails you can change a $5 socket instead of a $300 fuse box, not to mention the labor saved. But the chances of any engineer listening to any one of us is remote, at best.

 

Agree with everything.
Another repair approach given we are stuck with the "relay on a board" design would be to unsolder the original relay. Then take a relay socket with pigtail, solder the 5 wires onto the board and run the pigtail outside the fuse box. Did this with a washing machine.

 

elusive 303
it's a nonservicable relay. Inside the fuse/relay box. Fix is to get another fuse box

 

The last entry on this thread was over a year ago.
There are several options to fix this issue.
The CJB (fuse box) is no longer available new, so any used unit is going to have a used relay in it, too.
There was someone on ebay that used to service fuse boxes - send it to them, new relay installed, returned.
If you're handy the relay can be replaced, the relays are available.
Both, of these methods require removing the fuse box.
An external relay can be added without removing the fuse box, but again, need to handy with wiring.

 

Found a potential work around by wiring in an external relay....will let y'all know how it goes tomorrow. Instructions were simple; terminals listed below:
85: Connect to a wire that is hot only when key is on (Pin 3 of connection C270B/Tan & Red Wire)
86: Connect to Chassis Ground
87: Cut Dark Green/Yellow wire from 4 pin connector (goes from circuit board relay to FP). Connect 87 to the outbound wire. (leave a few inches in case you F up and need to re splice the original back together)
30: Connect to bolt at incoming power connection to fuse block (its at the bottom underneath the cover). Between the incoming power and the relay, splice in 30A inline fuse.

All told, some 14g wire, 14-16g male and female connectors and T splices...If it goes well, I'll update....If the guy who charged me $50 to diagnose the problem as a faulty fuel pump is reading this, THANKS! It was fun dropping the tank with 20 gallons of gas in it IN THE RAIN!!!!! (joke's on you; it really WAS fun!)

 

That should work, it is different from OEM in that the fuel pump will be on all the time the ignition switch is in RUN or START.
OEM: When the ignition switch is turned from OFF to RUN the PCM will enable the fuel pump relay for 2-3 sec to prime the fuel rails, then shut it off until it sees START or the Crankshaft Sensor spinning, not sure exactly what the logic is in the PCM.
That will be a continuous 15A draw whenever the Ignition Switch is in RUN and the engine is not running.
The PCM logic then keeps the pump running with the switch in RUN, until the ignition switch goes to OFF or the Crankshaft Sensor stops spinning, again not sure about the PCM logic.
From a safety view I would guess the PCM will turn off the fuel pump if the Crankshaft Sensor stops and the ignition switch is still in RUN, which could happen in an accident, but in that case the Inertia Switch hopefully will do its thing, too.
I like the power connection at the battery wire (RD) post at the fuse box, definitely add the fuse or a marine breaker, 20A or 25A would work, too. OEM is 20A.
I haven't had that apart before and didn't know that's how the battery was connected to a fuse panel.
The 4 ga RD battery wire does not have a fusible link in it, I'm going to add a 150A marine breaker to ours near the battery.
You didn't say what size relay you used, I used a 40A rated relay in ours.

 

 

I had the same problem man its inside the fuse box it's a relay on the motherboard

 

Yeah, don't wire an external relay with the relay on a hot in RUN or START circuit. Better to tap into the wire that the PCM originally uses to control the fuel pump relay, just find the correct wiring diagram (google is full of them) and dig out the wire.