Hi, I have a 1997 F150 4.6l, recently it has been draining the battery, I did the test for parasitic draw and the reading in the multimeter goes from 0.02 to 0.15 ma back and forth after an hour of connecting the multimeter. When I pull the fuse that says "ignition B4 & B5" the multimeter drops and stay 0.01 steady, Does anyone know where that fuse goes to? in the manual the fuse box says " fuse #30 50A IGNITION B4& B5"
Thanks for your help.

 

Which fuse number is it?
In the Cab, #11, 30.
In the engine bay, #8, 17, 18, 24, 25, 28.
This is according to your Owner manual.

 

The fuse is located in the engine compartment, fuse # 30 50A Fuse ignition B4 & B5.

My user manual

 

If your looking into a Haynes book , it's not the >Ford< Owner manual.
I am looking at Ford's 1997 F150 first printing from Ford's official Helms website at your correct owner manual, beginning Page page 137 through 142.
The 50 amp fuses are only at locations 15, 20, 21 and 22 in the engine bay distribution box located between the master brake cylinder and the intake air filter housing..
The only location #30 is in the cab panel and it is a 30 amp fuse.
There may be two other locations with small fuse holders. One has 3 fuses, the other has 6 positions with only 3 fuses slots filled..
These are shown on pages 141 and 142.
If you have something different, I can't help.
Until we get this solved, I can't help you.
Good luck.

 

The picture you are seeing is from the owner's manual that came with the truck, tomorrow I will take a picture of the actual fuse box in the truck and of the page in the manual that shows the location of the fuses.
Thanks for your help.

 

That is absolutely a Ford manual. Looks like mine.

 

According to both the owner's manual downloaded from Ford's official website and the factory service manual, there is no fuse #30 in the under-hood fusebox.

Is this an F150 built-in North America or was it built somewhere else in the world for the international market?

 

On my 1997 4.6 it says fuse 30 is for the PCM relay and ignition coils and it's 30amps.

One thing about those relays to the computer is they have diodes to allow a one way current flow. Took me a long while to figure that out on my Hyundai. The truck has separated diodes, there's two in my box, under the hood and I believe one was for the air conditioner if I remember right. AND they can work intermittently, ask me how I know.

 

Wrong fuse box.

The diodes cannot cause the OP's issues.

 

https://www.thebatterygenie.com/how-...-a-test-light/
In normal circumstances, parasitic draws less than 75 milliamps are normal; any parasitic draws exceeding 75 milliamps will quickly drain the battery. Battery drain can occur when an alternator has a bad diode. Current can flow from one end of an alternator to the other when it has a good diode.