What is on the other side of the firewall from these 2 a/c lines? The a/c is not blowing cold, but the compressor, dryer and expansion valve have been replaced and the smaller of these 2 lines is very cold when engine is running but the other is not cold at all. Should they both be cold? Is there a control valve on the other side that maybe isn't working or is something plugged up? Any help/suggestions would be great. Thanks. If it matters, I noticed that the heater isn't blowing hot either.