Hvac temp control issue after stereo swap

[Julio Jones]

I recently replaced the og head unit on my 99 100 series. Should have done it 10 year ago! Unfortunately I am now having a issue with the hvac system. Blows very cold at the lowest setting (as it should) but any adjustment of the temp knob and it blows extremely hot, no middle ground. Where do I start to diagnose this? I pulled the trim panel under the steering wheel to run wires for microphone and Sirius xm antenna. Possible I caught a mixer servo motor arm? Any thoughts are appreciated! Thank you!

 

[89BIGBLUE]

There's a cabin air temp sensor right below the key on the panel you removed during install.
If the white hose is not connected to it, it may give you issues like what you described.

 

[3_puppies]

X2 to the above
the hose and sensor are behind the small louvre

 

[Julio Jones]

There's a cabin air temp sensor right below the key on the panel you removed during install.
If the white hose is not connected to it, it may give you issues like what you described.

Got it! White tube not connected and sensor not plugged in. That's what I get for working in the driveway after dark. Thank you all so much!

X2 to the above
the hose and sensor are behind the small louvre

Thank you!