You can pretty much ignore the whole 4 to 7 speed conversion part of it. That is basically a standalone system that only connects to the rest of the HVAC system via the fan speed control wire that runs to the blower resistor. If you had an issue with the power to the resistor, the ground, the resistor itself, etc. it wouldn't keep the bezel or radio from powering on - you just wouldn't be able to get the blower to run.
Im confused about which configuration you had where the radio came on but you had no climate controls working. There's 3 connections for the conversion harness.
1)The dash harness plug that used to be plugged into the old bezel
2)The plug on the back of the new control bezel
3)The HVAC module that mounts behind the dash
It sounds like nothing worked when everything (1,2,3) was connected. What other combos (1,3),(1,2), etc. did you try and what was the result with each?
Im confused about which configuration you had where the radio came on but you had no climate controls working. There's 3 connections for the conversion harness.
1)The dash harness plug that used to be plugged into the old bezel
2)The plug on the back of the new control bezel
3)The HVAC module that mounts behind the dash
It sounds like nothing worked when everything (1,2,3) was connected. What other combos (1,3),(1,2), etc. did you try and what was the result with each?