2000 Jetta A/C compressor only comes on when moving above 10 mph

2000 Jetta A/C compressor only comes on when moving above 10 mph. off at idle. Car runs great no fault codes at all climatronic module no faults.
What started the issue: pulled dash to replaced heater core, evaporator core, expansion valve. Put all back together went to charge A/C unit and no compressor at idle. Put car on a charging machine and forced Freon into the system. Super cold when compressor is on, at idle A/C clutch will not engage. Hooked Vag-Com and HVAC system shows compressor off by “Missing Engine Speed Signal”. Car engine speed is perfect and the instrument cluster tach runs smooth. Replaced fan controller still no change.
Any Ideas? I'm guessing I must of forgot the speed sensor wire somewhere. Help

http://wiki.ross-tech.com/wiki/index.php/00529
This is what I saw at rosstech


The fact that the HVAC failure seems RPM-related is weird though.
Engine speed sensor corroded/greasy maybe?
edit: serpentine belt / tensioner good?
AC clutch seem normal?

I do have engine speed everywhere else on VAG-COM, but when I go under the HVAC section I don't have engine speed. I run a system test with ross-tech and the compressor comes on. Belt and tensioner is new and above 10 mph the ac system will freeze you out. There got to be a wire broken or not hooked up when I pulled the dash out to change out the heater core.