HVAC challenges

[911tracker85]

got the 944S back on the road.

the interior vents blow HOT air, so checked the HCV with mightyvac and it works. not feeling any vacuum from the connection to the HCV, so zip tied closed and hot air stopped.

and the AC is inop. started checking and cannot get the compressor to engage when I jumper the low pressure switch.

so, before I tear the dash out, wonder if anyone knows if both could be caused by the HVAC control module in the dash.

reading the Clark's garage notes, searching threads, and starting to dig into the WSM.

[16vCorey]

Both could definitely be caused by the HVAC control head.

[mueller944s2]

AC could be the relay

[mhariush]

Blows lots of hot air? Probably a broken heater clip. They're a couple of bucks, get some spares.

[911tracker85]

mhariush,
my 87 944S is also blk/blk. PO developed heath issues and stopped driving much, and it finally stopped running. sat for a couple years.

very nice cosmetically and almost perfect leather interior. so just had to buy it and bring back to life. now running great and love the pull/sound of the 16v motor.


I have already checked the flap clips in the footwell and they are good and working. with the HCV zip tied closed the hot air stops.

I have not checked the AC relay yet.... trying to find what all relays, sensors, etc in the AC circuit that I need to check. did this to my 928 a few years ago, and it still blows very cold.

but with two different HVAC failures on this car, suspected I need to start pulling the dash.

[mhariush]

gotcha. Maybe I didn't read carefully enough I'm pulling apart an 87 S now and I've just started taking out the HVAC, but had to stop as I couldn't get it out. There were some bolts there that I didn't see i think. So if you need one, I have one that was working according to PO.

[911tracker85]

great as I may. not sure how I will verify it the HVAC controls are bad.

it will be another week before I get back into this issue. spring time 'honey dos' galore this week.

[pfarah]

Just a friendly suggestion; you may want to replace the drier when you get to the point of recharging the system. It will make a strong difference in AC performance.

[911tracker85]

pfarah,
I actually plan to replace all the accessible O rings, drier, and have the AC hoses rebuilt. when I get into something like this I have learned it is best to just do it all WYAAIT.

but have not had time to get back into working in this.

thanks again for all replies/ideas.