I have a 1999 F150 Lariat, I noticed a couple of weeks ago that my truck has a leak, the leak is in the passenger side, I noticed that the carpet near the door was wet, so I pulled off the scuff plate under the dash and the kickplate by the door and there is standing water where the wiring harness is running. I popped the rubber grommet off and got the water out by moving the truck so the water ran out. I went and resealed the area around the passenger side of the windshield with translucent RTV, I don't know if the windshield is leaking, the windshield was replaced 4 years ago and I had carlite come out and reseal it when it leaked. If y'all have any ideas, I would appreciate it.

 

Most likely the windshield. Rtv isn't going to cut it. You need factory spec urethane elastomeric

If it is coming in the wiring harness, that needs to be sealed up as well

 

Third brake light? That's where my 2005 was leaking. This stuff worked great. Good luck
https://www.homedepot.com/p/DAP-2-8-...0756/202061328