i have a 86 with electronic ac control my question is my shop manuel for my year shows 5 vacum motors in my programer but the one i have has 6 it has been replaced before so i dont think its the correct one but not sure does anyone know for sure if the 86 has 5 or 6 my ac will not blow from proper vents and codes come up as open feedback potentiometer dont know what thats is but am thinking that if its the wrong programer maybe could cause all my problems sombody please help getting hot in ft lauderdale

 

....i think you have to be sure that the clips (if any) that connect the blend doors are not broken or stripped like one of mine was....also, at the firewall at the distributor (assuming that the 86 is set up like the 88) there should be a small vaccum line running to the plenum that, if broken, clogged or detached, should inhibit the the diverter doors from being were they are supposed to be as selected on the control panel....

 

Sounds like you have two different problems.

Air coming out of the wrong vents and a blend door motor problem.

Has the HVAC ever worked properly since you've owned the car?

I'm looking at a Helms for an 89. I'd think an 86 would be very similar.

At the AC Programmer there are 6 vacuum hoses at the nipple connection. There maybe a unused nipple.

#1 Orange hose is for Outside Air valve actuator
#2 Pink hose is for Rear Mode actuator
#3 Dark Blue hose is for Front Mode actuator
#4 Red hose for A/C Defrost actuator
#5 Tan hose also goes to the A/C Defrost actuator
#6 Black hose is the vacuum source that operates the actuators and comes from the engine.

I think if you have no engine vacuum going to the AC programmer all air blows out of the defrost vents.

If that's the symptom, look under the hood at the passengerside firewall. There is a small black hard plastic vacuum tube that should go to a vacuum check valve that has two outputs and one input. One of the outputs is used to supply vacuum to the AC Programmer the other outlet goes to the vacuum storage ball used for the cruise control. The input comes from the engine.



If the DC motor that moves the blend door doesn't work, the air flow should still come out of the proper vents. Just the temp. coming out of the vents would be incorrect.

Turn the ignition on. Don't start the engine. Place the control head in Auto. and turn the blower motor off. Change the temp. by using the up and down buttons. The AC Programmer applies a voltage to the blend door motor to move it in the proper direction to adjust the air temp. You should beable to hear the blend door motor move as you press the up or down temp buttons.

As the motor moves, a voltage is sent to the AC Control Head which then sends the data back to the AC Programmer. If the voltage feed back is not correct error Code 01 is set in Mode #08 (System Faults).

Make sure you're examining the data correctly.

This is how it works on an 89.
When you get into diagnostic mode there are 12 Modes.
A minus sign indicates you're looking at one of the 12 Modes.

To look at System faults which is mode #8 you would keep pressing the Warm button until you see -08. To see if any codes are stored in -08 you press the Cool button. If you see 00 there are no error codes.
If you see 01, that would indicate blend door Motor feedback open.

To look at the blend door motor you drop the passengerside hush panel.
The blend door motor is bolted to the side of the black plastic hvac air plenum. The electrical connnector is an edge type connector and just pulls off. There is a metal rod that attaches to the motor and the other end of the rod attaches to the blend door via a plastic cliip.
You can manually move the rod. You should feel some resistance because you're moving the blend door and blend door motor. If the rod is free, the clip is broken.

If you get a 01 code, you can use a voltmeter and measure the feedback voltage going to the AC control head.

On a 89 at the motor electrical edge connector is a Dark Green/White wire. If you turn the ignition on and manually move the motor via the rod the DC voltage on the Dark Green/white wire should vary from 0 to 5 volts. If it does the manual says to replace the AC control head.

If there is no feed back voltage from the motor but the motor does move when you press the temp. buttons the motor is probably bad.