Dodge Repair: 03 intrepid; brake lights/radio/door locks, police car auction, good kharma

Question
Hi Roland!  Appreciate any advice.  A friend is going thru some tuff financial troubles and had to get a cheaper car.  It's an intrepid from a police car auction.  Has that high output 3.5.  Anyway I know the switch up the wiring pretty shoddy when they put them out to the civilian motor pool.  Well, he was driving it back from where he picked it up and it died.  Called me up cause he knows I like to tinker and he's broke.  He tells me he needs a new alternater which he had the money for but doesn't know how to do it.  Not mechanically inclined whatsoever.  I asked who told him...he said some guy...so I said "Lemme check first.  We jump it.  Starts fine.  Took off the cables right awya died. I figure...battery.   Let it run off my juice for a few minutes took cables off and kept running.  He still thought alternator as he trusted this guys opinion so I told him to go to the parts store so they can check it while it's on and running.  While following him I saw his brake lights flicker a bit...started thinking wiring....so as I followed rang him and told him to pop on the headlights.....after a 10 min drive.  Turned on the headlights...car died...still thought battery.  Jumped it again...same results...had to wait 4 mins.  I popped out my volt meter to explain to him how and y the alternator was working fine and it's prob ur battery because you have to remove the breather and guard to get the battery out...takes a bit of time to figure it out.  I finally convinced him to spend the money on the battery instead of the alternator and I put it in for him and told him the 35 bux he saved on the price difference which he wanted to pay me...well put it in the tank.  I figure good kharma might come back to me someday when I need it!  Anyway, put it in, runs just fine but now his stock radio, and his pwer locks for the doors quit working.  I checked the 10 amp fuzes for both and they were fine.  Any guess on what this could be?  It worked before the new battery.  Also, if it has security system how would it be reset ?  Would it be any different being an ex police car?   Thank you soooo much for any help!  Feel aweful that although I was able to keep it running for him, I screwed up his tunes and locks.   Glenn

Answer
Hi Glenn,
Check fuse I (30 amp in the box in the engine compartment) which in turns powers fuses 19 and 20 in the box behind the dash that power the door locks/radio and brake lamps. One of those three fuses may be subtley cracked and causing the flickering/loss of function.
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Thanks,
Roland
PS Good show on all the diagnosis and advice given your friend so far.