Will a defective Heat Control Valve affect the AC?

Yes

No.

__________________
CENSORED due to not family friendly words

Yes

__________________
To see my 129 parts for sale visit:
http://stores.ebay.com/The-Mercedes-SL-Store
John Roncallo

this made me laugh

although it has to be frustrating for the OP

__________________
0o==o0

James 4:8

"...let us put aside the blindness of mind of those who can conceive of nothing higher than what is known through the senses"
-Saint Gregory Palamas, ---Discourse on the Holy Transfiguration of Our Lord God and Savior Jesus Christ


Centrally located in North East Central Pa.

OP moved on and bought a Corolla. He doesn't have to to deal with autists like us.

__________________
CENSORED due to not family friendly words

Yes it will, because in Mercedes benz the heater core is kept cold by stopping the coolant at the control valve, the system adds heat as required to warm up the core to the desired set temperature of the control panel.

If the valve fails open the core is now fully hot - and will overpower the A/C system.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)