Put in some new trailer lights. Used these splice connectors for the side markers and the right rear light to attach to back running lights also. Easiest ones I could find to connect the side marker wire inline with the rest of the wiring for running lights. But was wondering about water proofing. I dipped them in liquid electrical tape. Will that be enough for corrosion control? Thanks. 

You don't need to water proof the connectors unless you plan on leaving your trailer in the water. If you try and water proof the connection and even a little water gets in, it will do more damage because once the water gets in, it will stay in the connector and not dry out like it would if left out in the air.  

Two words.  Dielectric grease.  

 

"Permatex Dielectric Tune-Up Grease protects electrical connections and wiring from salt, dirt and corrosion. Required for modern high energy ignition systems, dialectric grease extends the life of bulb sockets and prevents voltage leaks around any electrical connection. Also prevents spark plugs from fusing to boots. Suggested applications: marine and automotive electrical connections, spark plug boots, trailer hitches, and battery terminals."

Scotch lock connectors are easy but may not be the best choice in splicing. 

I don't care where the connection is, on any exposed wiring I solder and heat shrink every connection.  Bad connections or bad grounds are 99.9% of all  electrical problems.  Those connectors have no place on my rig.  They make me cringe.  Through the years, I have pulled hundreds of those off due to failure.  You may be ok for a while but they will fail.  Just know to look at them first when troubleshooting.  I also am a big advocate of Dielectric Grease.  Especially in open connections like the trailer to truck pigtail and all of my graph connectors.  I also use it on my soldered connections before I heat shrink.

15 hours ago, TOXIC said:

I don't care where the connection is, on any exposed wiring I solder and heat shrink every connection.  Bad connections or bad grounds are 99.9% of all  electrical problems.  Those connectors have no place on my rig.  They make me cringe.  Through the years, I have pulled hundreds of those off due to failure.  You may be ok for a while but they will fail.  Just know to look at them first when troubleshooting.  I also am a big advocate of Dielectric Grease.  Especially in open connections like the trailer to truck pigtail and all of my graph connectors.  I also use it on my soldered connections before I heat shrink.

Truth!