Hi, I have a 2010 Ford f150 and I got the rear left door ajar on the dash screen and I took it to a repair shop and they Fixed it for about 6months so a year later I finally had time to check it out and notice that one wire was just wrapped around an another wire and electrical tape together,it looks like an extension wire. then I noticed that there is no harness to unclip all the wires look to be spliced together and them are actually soldiered together. so I soldiered the loose wire together and recapped all the wires and the light is still on and saying rear left door aja . Any idea what is wrong? do I need to purchase a new harness and re wire it?

 

There's probably another wire that's either broken or some of the wire strands are that won't allow enough current through. Those fast repairs done in the flex area of the harness usually don't last. If some wires cracked/broke others are to follow. I'd just replace the harness.

 

For whatever reason, the circuit is still "open". You need to actually test the circuit so you can find and fix the remaining fault(s).