I am copying this from another forum, as I had the exact same issues. Not sure who put this out there but it has saved me hundreds of dollars and hours of confusion.. Hats off to this guy, Thank You


Interior lights only work when ignition "ON"
Headlight switch does not work unless ignition "ON"
Power door locks will not work from Keyless entry or the switch on the door panel
Radio does not power on
Hazards will not turn on unless ignition "ON"

The fix is easy. First locate the fuse and relay box under the hood on the driver's side. It is in front of the battery and unscrew the lid. The IOD fuse is located in my 2003 Dodge Ram with the 5.7L under fuse #51 labeled "CLUSTER, RADIO, UNDERHOOD LAMP" **see attached pictures for further clearer location... It is housed in a separate fuse housing with a black clip on top that is very similar to the yellow airbag fuses (I would suggest not messing with the airbag fuses trying to figure out the clip, it can be a bit tricky).

Once you have located the fuse location you can then pull up on the clip assembly, you can use the included fuse puller (the yellow tweezer looking things near the bottom) to unclip the top side of the clip holding the fuse. Once you have the fuse out you should check to see if it is still in tact. If that windy strip of metal in the middle of the two pegs is at all broken, the fuse is blown. If it isn't but you have these problems, I would try replacing the fuse to make sure this isn't the problem. If you don't have a spare 20A fuse on hand you can pull one from a lesser used accessory such as your cigar lighter or center console accessory power. Your car will work without these fuses, but it will just make it so your cigar lighter or center console power is deactivated until you get a good 20A fuse into the corresponding spot. Once you put the good fuse into the clip and push it back down into the slot, your interior lights should illuminate when you open a door, your door locks should function, your radio should work.


Now for those who have paid for a dealer to look at this problem to no avail I would suggest asking for a refund of your money, or at least some type of prorate. If you went in and said anything like "the radio won't work" they should have checked the radio to find it does not power on, then check the Dodge Ram service manual which in it's trouble shooting guide says to check the IOD fuse when that symptom is present. If they checked the radio, then looked at the service manual, they have ignored the proper procedure in fixing your problem.

Hopefully this helps someone.

 

Wow just spent about four hours trying to figure this out then read this and fixed it in about four miniuts haha
Thanks