lights pulsate while heat is on. noticed this...

One other thing to check is the tightness of all connections in the 12v circuit. I found a bunch of loose terminals when checking mine. Some of my connections terminated in a buss bar inside of an electrical box along the frame close to the battery. Pay close attention to the ground wires as well.

Start with those showing in your photo and work back from there. What you are describing isn't normal.