need wiring help

2000 ford mustang GT 4.6L so there are no trouble codes and the problem im having is the battery drains over night the battery is ok i tested it with a load tester so then i did a parasitic draw test and in the under hood fuse box i found that the I/P fuse is the one thats draining the battery so then i took the fuse out and did a voltage drop test it showed 0.00 but then i put a load on it with an incandescent test light then my dvom showed 12.33 and i took the test light away and it dropped to 0.90 volts and slowly kept dropping tell it hit 0 volts again and my question is is this a bad wire or is this a bad ground the test light does light but takes a second to light and is vary dim need help finding pcm location and ground 204 and 400 cant seem to find them

To drain a battery overnight takes a fairly large current draw way above normal parasitic drains so if it is a parasitic drain it would have to be from a system drawing at least 0.5 amps. On modern cars with computer modules that can take up 30 miutes after key-off to go to sleep mode parasitic current drains are difficult to pin down so first of all you need to be 100% it isn't the battery.
Although you have done a heavy load voltage drop test on the battery this won't always show up a defective battery. The drop test is very good at getting a clear pass/fail result if the battery has a shorted cel (also called a "gassing cell" or "dead cell") even then the battery has to be loaded to at least 1/3 to 1/2 the CCA of the battery or 3 times the AH capacity of the battery --- with your car's battery that will be a test load of 240 to 300 amps that needs a carbon pile tester as most battrry the most common testers only draw 100 amps.
Even at 250 amps What a voltage drop test won't show easily a battery that simply isn't holding charge, keep in mind that every time a battery is discharged it is damaged and with every discharge -recharged cycle the real number of amp-hours the battery can store is reduced. The test I would do is either fully charge the battery with a battery charger or run the car for sufficient time to charge the battery. key off and observe the battery voltage it should drop from something like 13.1 immediately after the key off to say 12.5 to 12.7v after a minute or so. Next turn the lights on for 2 minutes -- normally I wouldn't expect good fully charged battery not to go below 12.3 v with the lights on and recover to 12.4 to 12.7v a minute or so after the lights are switched off. Now disconnect the battery and leave it disconnected for at least 12 hours.
Check the battery voltage before reconnecting if there is a noticeable drop in voltage there is a battery issue, next reconnect the battery and turn the lights on for 2 to 3 minutes again the voltage should not drop below about 12.3 volts and it should recover to at least 12.5v a couple of minutes after the lights are switched off.

Derick wrote: need help finding pcm location and ground 204 and 400 cant seem to find them

This is the back side of the dash.



All it says for G400 is "At Left Rear of Vehicle".

PCM "Behind right kick panel"

SWEET thank u so much ware did u find that in car diagram?

Well I’m not 100% sure but I remember a while back tracking it down to the gem how long does it take the gem to shut down??? And ik for sure that what ever the problem is it has to be on the instrument panel/PCM 40 amp fuse because if I take that fuse out the car can sit for a a long time and only drain down a little bit and with the fuse in it will drain the battery way down to just 1-3 volts overnight and if I remember correctly when I did the current draw test this was last year around now and I used a inductive amp clamp with every thing closed except for the hood and the hood doesn’t have a switch and I roled the window down and climbed in and out the window and waited 35 mins before I took the measurement and I believe it was around 400 milliamps

That 40 amp fuse feeds many more, smaller fuses. Let's see if we can narrow it down a bit. If there is current flow through a fuse, there will be a voltage drop from one side of the fuse to the other. The drop is very small, but it will be there. Set a multi-meter to Milli-volts and, with one test lead, touch one of the test point of the fuse. With the other test lead, touch the other test point of the same fuse. You would expect to see 0.0 milli-volts and, if there is NO current flow, that is what you will see. BUT, if there is current flow (i.e. a parasitic draw) you will see a reading of something higher than zero. Maybe .10 mv. Maybe, 100 mv. The bigger the draw, the higher the voltage reading will be.



Here are the fuses that 40 amp fuse feeds.