A/C Weather Depicted Non-Op??

[MPDano]

My A/C works like a charm, except if I leave my car outdoors in the heat all day, then try to use it. It then will not turn on, you kinda feel a faint breeze but almost non detectable from the center vents.

If I park my car all day in the Underground Garage where it's cool, the A/C works absolutely perfect. Even once you start driving in the outdoor heat it works great. It's like it's kick start get's disabled.

What cause the hot ambient temperature to somehow keep the A/C from running?

FYI, does the Sensor in that lower spoiler intake tube to the Alternator have to do with this? I removed it since the hose wasn't present.

[Mrmerlin]

first reconnect the outside temep sensor.
Then try replacing
the HVAC relay,
the blower relay
and the window relay
do one at a time.
Dont ask why

[MPDano]

Will do MrMerlin. Also heard of a Relay in the HVAC Unit itself. I wonder if all the buzzin noise at times has anything to do with this.

[Mrmerlin]

in the HVAC duct is called a resistor pack,
its quite different than a relay

[neil30076]

Leo, make sure the chain is good from the duct sensor, the thermistor in back of the 'sniffer' in the right top side of the console. Open sensor in the duct as Stan indicated is the same as ( IIRC) lowest temp outside, so air will not come on - or be very minimal.
If you recall, I had the same problem and it was a broken wire behind the console that made the chain open. Symptom is also ( or wa in my case) no blower fan speeds, there is a way to test it with a 680 ohm resistor jumpered in the right place. I have the test procedure for the whole chain if you need it.

[MPDano]

Originally Posted by neil30076

Leo, make sure the chain is good from the duct sensor, the thermistor in back of the 'sniffer' in the right top side of the console. Open sensor in the duct as Stan indicated is the same as ( IIRC) lowest temp outside, so air will not come on - or be very minimal.
If you recall, I had the same problem and it was a broken wire behind the console that made the chain open. Symptom is also ( or wa in my case) no blower fan speeds, there is a way to test it with a 680 ohm resistor jumpered in the right place. I have the test procedure for the whole chain if you need it.

Ok, sounds like I need to at least put the Thermister back in the chain and zip tie it up there somewhere.

[MPDano]

Ok, put back the Thermister near the Alternator tube. I had to zip tie it near there as I am missing the hose and supporting pieces. The electrical is connected back. As a test, I ran with the AC on this morning to work and it was brrrrrrr cold. The test is if it works when I start driving home after work.

[riber.bentsen]

You need that hose in place bro, otherwise you'll be sucking crud and stones into the alt. fan - you can guess what happens from there

[MPDano]

Originally Posted by riber.bentsen

You need that hose in place bro, otherwise you'll be sucking crud and stones into the alt. fan - you can guess what happens from there

I wouldn't know how to install that hose even if I had it. Can you take a pic of yours? Obviously it would be facing the rear, correct?

[riber.bentsen]

I'll be taking of the wheels and inner fenders for the MM+OPG job this weekend, I can snap some pics then?

[MPDano]

Originally Posted by riber.bentsen

I'll be taking of the wheels and inner fenders for the MM+OPG job this weekend, I can snap some pics then?

Cool! No hurry. All can benefit for your pics too.

[neil30076]

Leo, good picture at:
Alternator cooling hose replacement - Rennlist Discussion Forums

[MPDano]

Thanks Neil.

Gave the AC a test after work and on "Auto" got hot air, but then moved the slider to "Bi" and got cold air and left it there till I got home. I didn't try and move it back to "Auto" as I was just happy to have nice AC on the drive home. Didn't want to jinx that.

[MPDano]

Just bought 6' of the 2-1/2" Duct Hose off eBay. Should be enough to do both my 928's.

2.5" X 6' AC / HEATER FLEX DUCT HOSE- NEW - eBay (item 230549149468 end time Jul-08-11 08:24:51 PDT)

[harborman]

As I recall the hose with sensor, comes from alternator into fender-well, goes in front of the fender then loops around, then down. Mine was broke so I spliced it with a short piece of PVC and some clamps.