I am being to dislike my Ford. For the past few months the truck has been less than reliable. I will spare you all the details but here's a summary. I have a 2008 Ford F150 Lairat 4x4 Crew Cab Pickup. Back in December 2016 I had a no-crank/no-start. This was the start of my troubles. The truck would intermittently not start which was frustrating. I ended up replacing basically every part in my starting circuit (battery,starter,NSS,ignition switch,battery cables). After a few weeks I was stuck and assumed the problem was the PCM or the fuse/relay box. I took the truck to the Ford dealership and it was ultimately diagnosed as a bad PCM. I replaced the PCM and now the truck has no problem starting but the battery light comes on and it says check the charging system. I've charged the battery fully and used a multi-meter to check the battery while the truck was running to check the alternator. I charged the battery to 13V and it was putting out over 14.5V when running. I took the truck to O'Reilly and the guy said the same thing. According to him the alternator was fine because it was charging the battery while the truck was running. I ended up doing a parasitic draw test this evening. I disconnected the negative battery cable and hooked up the multi-meter to the negative battery cable and the negative battery post. I was getting a reading of about 0.5 or -0.5A draw.
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Is it possible that I could have a bad alternator that is draining the battery when the truck is off? Is there anything else I can do besides going through and removing each fuse one at a time and looking for a change in the reading on the multi-meter? I asked them to check it out when it was at the dealership but apparently they didn't look into it. Also if anyone knows about the interior dome light switch I'm curious about something. When the switch is slid to the driver side the light comes on (I can't remember if it was with the door closed or open) but when I slide it to the middle and passenger side the light doesn't come on. I've seen posts about the third brake light leaking and I had some flickering of the light so I'm wondering if something is going on there. Thanks for any help.

 

Alright so I just located the problem. I pulled fuse 21 (cluster keep alive) and the reading dropped to 0.0 (I was still on 10A scale). Now what do I do? What is my next step?

 

Here is where I'm at. I disconnected the negative and positive battery cables and left my headlights on for multiple hours (I read that this drains the capacitors in the instrument cluster and "resets it". Tonight I went out to the truck and turned the headlights off, closed the door, and reconnected the positive battery terminal. I hooked up the multi-meter and the reading was around 0.5A still. BUT to my surprise the number dropped to 0.0A after a little while! I was surprised when my friend said it was at 0.0A but it was. I went to the back passenger door and opened it to show him that the number would change. I closed the door and the number went back down. I opened the driver side door and closed it but the number never went back down. I'm kind of confused. I got in my back seat and checked out the headliner and realized my third brake light is leaking. I noticed my interior dome light flicker the other day so I think the rain we've been getting leaked inside and shorted my interior dome light.
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Can someone answer a simple question for me? For the interior dome light in the back seat what are the 3 different settings for the light? I think to the driver side the light should always be on, middle position is off, and passenger side position it should come on when door is open. Is this correct?

 

if I remember correctly the dome light settings should be:
toward driver side: on
center: on when door is open
toward pass. side: off

 

Thanks! I'm not sure if it's a loose connection or what but the little roll **** switch that adjusts the brightness of the instrument cluster panel by the steering wheel is messed up. I moved it around and found a good spot where it works. Now when I press the unlock button on key fob the cargo lamp lights up and when I open the door the interior dome light lights up. Everything is working as it should and the parasitic draw was less than 0.01. I also used some silicone to seal my third brake light better because of the known water leak. Hopefully I don't have anymore problems for awhile!