When I turn the fan on and through all speeds - air only comes out the window defroster area....no air coming out any of the dash vents toward the driver/passenger.

Any thoughts?

 

It should only come out there with fan knob fully on. If you have airflow at lower fan speeds it might indicate no vacuum to the actuator since vacuum CLOSES that vent.

 

Go through these and you will find the problem. The word doc is a supplement I made to assist in going through the diagnostic process

 

Thanks...to be precise...I know my A/C does not blow cold, as my system has not been charged in years....but it still should blow air, correct?

 

You won't get much airflow elsewhere if the demist flap stays open all the time.

 

Hi Warron... I just read thru the step by step article... More than anything it simply says replace ecu/m... Can that be right? What if that's not possible? Parts are hard to find.

anyways, test 32 and 33 (my problem area) I get only 1volt at pin 20... Does that mean replace the while module or can one trace back the prob at the ECU and replace a component, in your experience???

 

The ECU is a pain to repair because all the traces run inside the PCB making fault finding very difficult.

Unfortunately from your test it means there is a fault on the ECU PCB, most likely a faulty driver transistor. If you know someone with good electronic fault finding skills they should be able to find the transistor and replace it. I have done this with my ECU for a faulty solenoid driver.

As a temporary measure you can bypass ECU control of the compressor and wire the compressor to come on when the AC is turned on. Then keep a lookout for a replacement ECU I found one on eBay last year and bought it. Be aware that there are numerous versions of this ECU so if you do buy one make sure the numbers on the ECU match yours.

 

On pp 85 of the Drivers Handbook (for my '95), there is a rendering of the various vents and their function. For the "fascia center vents", it says: "Only cool air can be supplied through these vents. When the system is providing hot air, they are automatically closed off." Even if your system is not charged, you should be able to check airflow from these vents by (1) Have the motor running. (2) Set the button function switch to "Manual". (3) Set the fan speed switch to "med". (4) Set the temp control to the coldest setting. (5) This one I am a bit foggy on....I think I engaged the "AC On" button. There seems to be a magic sequence required for much of this to work. 8-)

 

My 89 will blow warm air from the centre vents, the 95 has a different ECU and does function differently than the pre 94

The diagnostic procedure that he followed is for the correct MY and indicated that the compressor clutch output from the ECU is not functioning.

 

Not sure if this relevant but ...
I had a similar problem and told the mechanic about possible circuit board problem and other common possible causes but it turned out there was a cache of acorns. The car purchased had sat for while and squirrels had made themselves comfortable.
Good luck.

 

I had the same thing after fitting a new amplifier, no air coming through vents, so on a warmish day I gently adjusted the new amp and with a click from inside the amp all the vents opened and I have cold air. But don't be to quick to judge and don't worry till its gassed up.