Interesting Air Con / Heater issue

[Jon_boy]

Ok so whats happening. In the winter the heater wasn't getting very warm at all, flushed the cooling system and back flushed the matrix. Had a nice lot of rusty water out did this a few times and was flowing full bore so no restrictions all good. Heater then seems better but not right. Bleed it well no air in system. Checked all the flaps/motors and rods i could see with the glove box removed all looked to be working correctly. So just left it, until now when the hot weather has appeared! Guess what now the air con is only semi cold. I had re gassed it in the winter replaced a couple o rings on the condenser fittings all ok. Have now noticed the compressor is running all the time weather the ac button is lit up or not. Well that might explain the heater problem if the air con is always on. with the engine off it turns free so the clutch must be ok. Not checked supply yet. Tried the old hold the buttons down for heater diagnostic and flashes up top LED on fan (not sure what that one means) one for front demist/windscreen which says solar sensor (was in the garage at the time) and one feet/face which says ambient air temp sensor(Have i got these correct?), so had a look around for it behind the bumper found a connector but no sensor. Called Keron and he sent one down, plugged it on and still the same codes. Is there a reset? Has anyone has anything like this before? Does anyone have a wiring diagram of the heater circuit? is there a separate ECU or is it all done in the control panel? Had the supra 11 years now and this is the first electrical fault not bad for a 25 year old car

 

Any help greatly appreciated

[Frank Bullitt]

Ouch, my eyes hurt Paragraphs would help

[Delboy52]

Here are the fault codes for the AC climate control.

 

 

http://www.jack-frost.co.uk/toyota_supra_air_con.html

[rider]

Are you certain the ac compressor is running and its not just the pulley turning as its on an electronic clutch to actually engage the compressor. There is usually a good 150 to 200 rpm tick over difference ac off to ac on so I can tell from the idle if the compressor is running or not. Though to get any kind of cool air in this weather your ac must be functioning so if you switch it off on the button and there is no drop in engine rpm then your compressor would seem to be running all the time, which would mean your clutch has constant power to it seeing its not seized in the engaged position. That would tend to say stuck relay.

 

As for temperature, when its 30C outside you probably aren't going to get super cool air at the vents. The best way to check if your compressor is good and your refrigerant charge is good is to tap a pressure gauge into the low pressure port. You should be around 60 psi with everything off and stood, then 12 to 17 psi with the compressor running. A correct level will also give you liquid running through the sight glass at the front of the car when the compressor is running. If you are seeing a stream of bubbles go past in the sight glass then thats another sign the system is undercharged.

[AndyJax]

In the users hand book it does say to expect a few bubbles in the sight glass for the first 30 seconds or so then clear.

 

This is what happens with my car which is fully charged and nice and cool.

Edited July 6, 2018 by AndyJax (see edit history)