Question-------------------------
Followup To
Question -
FOLLOW UP QUESTION : Is there a way to tell if the inertia switch is still good . Is it continuity or ? thank you DALE
Followup To
Question -
1987 Ford F150 4x4 Fuel pump is not working. I have replaced all relays & pumps; checked all fuses; & everything else I can think of. I finally wired the fuel pump direct to the battery & it worked fine. I pulled inertia switch out & found a burnt wire to the switch. Burnt where hooked to terminal on switch. Checked wires & have no juice in wires to switch. QUESTION : IS there a inline fuse on wires to inertia switch or how would I be able to get juice to switch ? wire goes through harness so I can't trace it. Need help THANK YOU Dale
Answer -
Hi Dale,
Sorry I missed this question before I left for vacation.
You can trace the wire by color code through the harness.
There should be a fuse in the fuse block.
If you haven't already found your problem and fixed it, please write me back, and I will see if I can find a schematic to look at.
Van
Answer -
Hi Dale,
I dug out the book, and there are several different systems, depending on engine size, single or dual tanks, 4X4, fuel injected vs carb.
But all have a switch, and most are powered by a fusible link, rather than a fuse.
Some have a pump relay, also.
The switches I looked at only have two wires, so continuity through the two connections would be necessary.
But I would be looking for the fuseible link, which looks like a splice in the wire, probably near the fender mounted solenoid.
Keep me posted, and send engine size, and fuel system type if possible.
Van Hi Van ANSWER to FUEL SYSTEM : 4.9 liter ; Dual Tank ; 4x4 ; Fuel Injected ; Has two relays ,I have changed both ; Has in tank fuel pumps and fuel pump on frame , have changed them to ; has fender mount solenoid ; Has little block looking things on wires by solenoid ; QUESTION : Are the blocks the fuseible links ? DALE
AnswerThe little blocks are the connectors that connect the fusible link to the wire itself.
The link is between the block and the battery bolt on the solenoid, although it is possible for the link to be burned out inside the block. Piercing the wire insulation on each side of the block with a test light is how I would check them, or actually, just pierce on the opposite side from the solenoid, and check right at the solenoid.
Now, in my manual, the power that supplies the ignition switch, is the same fusible link that supplies the fuel pump relay.
That relay has four wires connected to it....
A red, and a tan/green, which operate the relay,
A yellow, which is battery power from the solenoid terminal green fuse link,(also supplies ign switch) and should be hot all the time,
And a brown wire, which goes to the inertia switch, then on to the frame mounted pump through a pink/black wire, and also to the fuel tank selector switch through a red/white wire.
On the relays, the yellow wire must be battery voltage on the yellow wire of BOTH relays. The other relay is the EEC power relay, and when it is energized, it supplies power to the injectors, several vacuum control solenoids, and the FUEL PUMP RELAY OPERATING CIRCUIT.... WHICH IS THE RED WIRE,so if the EEC relay doesn't work, or have power to the yellow wire, the fuel pump relay can't work, even if its yellow wire has battery power.
Like I said, the yellow wire on the fuel pump relay gets its power from the same fusible link that the ignition switch gets its power, so if SOME ign switch controlled items work, that fusible link, (green), is probably good.
But the power relay yellow wire gets its power from the BROWN fusible link at the fender mounted solenoid.
THERE IS ONE MORE FUSIBLE LINK...AND IT IS RIGHT AT THE EEC POWER RELAY.It is blue, and connects to a red wire. It carries the power from that relay, to all that stuff I mentioned, including the fuel pump relay red wire, all the injectors, etc.
I don't have a way to send pictures, so I hope my drug-out description is understandable.
Basically...check for power at both relay yellows,
Make sure both relays are working,
and check the blue link at the power relay.
Good luck,
Van
