I am wondering where to start troubleshooting my no heat problem- by no heat I mean even when set to hi, the air blowing out is ambient. The hoses going to the heater core are both hot to the touch when the engine is warm so I don't believe its a trapped air thing... Where do I begin with verifying the operation of the various flaps?

 

If the hoses to/from the heater core are hot then I think you have narrowed the problem down to a heater flap issue. The flap has failed and dropped down -- or stuck in an fully up position -- so no air is routed through the heater core.

With the auto climate I believe the Porsche diagnostics computer can "talk" to the controller and command certain operations and and allow the tech to trouble shoot the system

With the manual system I'm less sure the diagnostics computer can do much with it.

What can you do?

Well, if you operate the heater temperature control does the air speed or flow change? The air speed/flow (something) changes perceptibly (I can hear it and feel it) as I cycle the heater temperature control from low to high using the temperature control button even if the engine is cold. I take this as a sign the air flap is moving and routing air around/past the the heater core then through it as the temperature control setting is increased.

 

Where in the Southern Hemisphere do you live?

 

I am located in Lancaster CA

So when I have the vents configured as in the first picture, as I go from cold to hot, the air output transitions from the center vent only at max cold to the footwell and windshield at max hot.


When configured as pictured here, or any combination of windshield, center, or footwell only the air output does not vary as the temp control is changed.

 

I've been through Lancaster. Drove over from 395 then took 14 up to Mojave and then 58 over to Tehachapi and on into Bakersfield.

Unfortunately I do not recall anything of note. I just passed through in a hurry to get someplace else.

 

Nothing of note- hah that's pretty much true but its because all the cool stuff is hidden away from public view! There are some really cutting edge vehicles being developed just a stone's throw from the 14, you can probably actually see the buildings. Aerospace is the main reason the Palmdale/Lancaster area is as big as they are, I actually work in Mojave, but could not bear to live there. Plus, the 996 would look incredibly out of place in that area I would probably get shot at haha

 

Well, good news is my heater core is in great shape, as well as the foam on my flap... bad news is the flap doesn't move at all.

Servo arm here I come!

 

I knew there was a lot of hispanics in Socal (lived there for a while)Now my old gardener , Manuel, is your HVAC mechanic!!!

 

Ay Caramba! Too bad I took French maybe I could communicate with it better haha
Well, the servo checks out, I put 12v to the motor manually and it moves just fine, both directions. Also confirmed no voltage from the harness side when cycling temp controls. Bad climate control unit is the answer I fear.

Also from https://rennlist.com/forums/996-foru...e-control.html my 12c command value varies properly, and as I manually turn the motor and move the servo arm, the 13c position value varies correctly. I hooked a multimeter up to the motor and there is nothing...must be internal to the climate control unit

 

Alright well a little logic and a multimeter can go a long way! I opened up the climate control unit hoping to find a cold solder joint or a toasted transistor, but on a whim I also wiped down all the contacts in the back and what do you know the servo came back to life! Definitely will reassemble with dielectric grease...