1999 Ford F150 fuel pump

check fuel pump relay and wiring back to the fuel pump

i can feel the relay tick but it only sends 0.05 volts to the pump

are you testing the volts at the relay or at the pump ?

at the pump. i dont know how to check the relay

mark the relay and switch it with a similar one
test at the relay for volts out

check fuse #10 its 20A
pink/black wire should have battery volts when key 1st on and when cranking
if not go back to the inertia switch if have it power at the switch then suspect and check wire between switch and pump

if no volts check for volts at the grn/yel wire
if have power replace switch
if no power check wire between switch and relay

there is no power on pnk/blk wire or grn/ylw wire

i swaped relays and it didn't change anything

i dont know what else to do

Checked the fuse and its OK ?

Remove the relay and check cavity #30 should have battery power if so use a fused wire and jump cavity #30 to cavity #87 DR/GRN/YEL wire
that should activate the pump if wiring and circuit OK if not have to check by the spare tire for a module and if have one check for power in and out

the fuse is ok.

i have checked the #30 and it does have power but havn't went any further. i will use a fused jumper and try that to 87 tomorrow. i'll let you know what i find. you have been so helpful. i just want to say thank you

that will activate the pump even if the key is off or on?
if that does it means the relay is bad?

there is a big round cylinder with fuel lines hooked to it but i have never noticed one before and have no clue as to what it is or does

Use a fused wire to power cavity #87
that should activate the pump on or off

ok i used a fused jumper wire from cavity #30 to #87 and it did activate the fuel pump.
what do i do now?

did you try new relay

no. i did swap relays but it didnt change anything.
should i buy a new relay and install it?

use a test light
turn key on check cavite #86 it should have power do you ?
red wire

i will check tomorrow and let you know.
will it only have power when the pump should be running?

Jumping 30 to 87 should get the truck starter
if pump coming on all wiring should be fine from the relay to pump
have to check relay control circuit

i dont have power to cavity #86.
what next?

RED WIRE SHOULD HAVE POWER
CHECK FUSE #18 IT 15A UNDER HOOD FUSE BOX
LEFT SIDE OF ENGINE COMPARTMENT
IF FUSE OK CHECK WIRE

fuse is ok.
red wire does not have power

red wire should have power
if no power check for a short between wire and fuse

i only found two wires that were solid red and tested both of them and they have .09 volts

30 has power 86 does not, red wire does not either.
where do i go from there

with key on check for power
if no power at red wire
check the wiring harness by the wiper motor

there is no power in the red wire by the firewall

OK lets try this
fuse #18 should have power if so and you don't have power on the red wire
you have a short between fuse and the relay


use a test light turn key on check fuse # 18
does it have power if so
check red wire you have to trace it to find the short

or run a new fused temp wire