Originally Posted by dieselguy
Although I can't help you right now, I will remind you of the old saying ... If it isn't broken don't fix it.
Another way I like to express it is: If it ain't broken, fix it till it is! So in attempt to guess what the red wire is, it may be a speed wire from the blower motor. Thr schematic a black high speed, a yellow medium speed and a red low speed. The wire you are holding doesn't appear to be red. The red wire appears to be of 2 conductor construction combined into a ring terminal. If you were to follow the wire to it's origin, and it happens to be the blower motor, you may have your answer. The photo shows red, black, and white. A shortcut is to just look at the blower motor to see if you find the 3 colors exiting it. It is always a good idea to cap off the stray wire. If indeed it is the low speed to the blower, and if it were to contact a grounded metal part during the motor operating, the motor will be damaged. Also a better schematic can likely be found by googling "Dometic a/c schematic". Then choose images. Give us a courtesy sound out if you find the answer!