Over the last 16 years I have had to pull my seat and raise the carpet to dry with a fan twice because of the third light. Mind is a club cab and by removing the jack on the passenger side you can see the water trail or channel to the carpet. This happened recently while deciding if I wanted to by a new light or gasket again I needed some kind of fix as I did not want to go the RTV route. I noticed a obblong hole in the side behind the jack. I took a 2 foot bar with a flat sharp end and cut the metal at the bottom of the hole and channeled the water out through the weap holes at the bottom of the cab until I decided what to do. And then foward of the hole I took a tube of Dicor and a straw an built a small dam I don't think it was needed but!!!! THIS IS A TEMPORY FIX but has worked sofar until I have time to fix it properly. The truck has been sitting in the rain for 2 days and still dry.

About the light it looks like it is warped on the bottom probably from heat and I don't think a new gasket will fix it this time. I have found 2 at JC whitney one has to be wired to fit about $39.00 and the other one is plug and play $69.oo.

 

I used the soft formable RV window sealent, its like a plumbers puddy, rolled it into the size i wanted, dropped it into the the grove on the light and tighten the 2 light screws a bit every hot day. Cab 100% dry now

 

I have used the puddy tape on my RV's before it is good for a long time. I have some silicone puddy tape it is used for seams on steel buildings once you put it on its stuck.

 

I had this problem for years on my '98. Someone on here told me to put a 90 degree elbow on the drain tube for the A/C on the firewall. A little silicone glue and a PVC fitting and no more wet floor board. The fan was blowing the condensate back into the cab instead of letting it run out the tube. Worth a look.