Need help locating coolant lines-99' E300
 

Hey fellas,
I'm installing a WVO kit in my car and have come to a roadblock. I thought I had "Tee'd" into the proper coolant lines for my heated tank. According to the instructions, the lines need to be connected to the intake and return coolant lines for the cabin heater. My connections are close to the firewall on the passenger side of the vehicle. There are two coolant lines running into the firewall, which are above the wheel well. My tank does not heat after I run the engine to temperature. Just a few quick questions:
1. Am I splicing into the correct connections?
2. Could my lines have an airlock in them? If so, how do I go about releasing the air?

I would really appreciate any help. Thanks for your suggestions.