If you are referring to the heater core cooling pipe is under the dash towards the center console kind of under the radio on the passenger side almost to the firewall, to access it you would have to take a panel off the center console/under dash that just pops out, run the engine, set temp to 90 degrees and it should get super-hot within seconds, I almost burned my fingers.

If you still see no difference while changing your A/C controls when changing the temp it could be the inner mechanism/vent that mixes the hot and cold to adjust the desire temp, the A/C system and compressor works at the same rate regardless of the set temp on the dash but what gives you the set temp is the mixer under the dash mixing heat and cold.

Good luck.

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The Stable:
Lamborghini Gallardo Superleggera/Full Carbon Package/Heffner Twin Turbo/ADV1 05.1 SL/STS Bumper, Wing and Bonnet/Wrap?
Ferrari 360 Chalenge Stradale/Fabspped Test Pipes/ADV.1 5.2.1 S.L. 20" Wheels/Michelin PS2
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Ducati Monster S4 RS/Razmoto Levers, Clutch, Termignoni Pipe, Handles and Mirrors/Sato Sets

Hey Exotic,

Thank you the advice! I will look into it.

Thank you

Kind Regards,
MRajeh

Sorry to bring this back from 2012, but I'm having a similar issue with my a/c blowing ice cold on the passenger side only but warmer in the middle and hot out the driver vent. Here's what I've checked so far when both dials are turned to LOW:

1. Compressor turns on, passenger side fan runs. When car is warm, both driver+pass fans run.
2. Checked all A/C fuses to be OK.
3. Refrigerant level is good. No refrigerant or oil leaks found.

I read in this thread someone mention the mixing vent actuator going bad. How do I test the actuator to verify?

check your battery, i had a bad battery and as soon as i replaced it everything was perfect.

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Lamborghini Gallardo
Lotus Elise
Lexus GS300

battery is fully charged. verified with dmm.