I have the dual electronic climate control in my 98 vert. First thing I noticed when I got the car is that the passenger side wont blow hot air.Driver side blows both hot and cold. Suddenly today I noticed that it got hotter than usual in the cabin, and I found that the passenger side also blew hot. Turned off and on the engine, and I was back to cold air from passenger side. Have tried earlier to pull the nr 27 fuse with no change.
The display on the control works fine, but many of the functions doesnt. The auto function doesnt work. The manual fan speed doesnt work as it should either. It doesnt increase speed as indicated. Its nothing or a lot.

Any tips on why its so many functions that does not work as they should?

 

It sounds like to me that the actuators are bad and/or the blend doors are out of sync. Do a search for both of these items and see if it helps.

 

I had to replace both my actuators (2x's) and the head unit. Pulling the dash is quick and easy IMO. Especially after doing it like four times

 

I think the actuator on driver side works correct, it will change from hot to cold as it should. The strange part and what I haven't found in searches of the topic is the head unit acting up. Like mentioned, all graphics are correct, but if I push "auto" the fan will not adjust automaticly. And if I press the + button on the fan speed it doesn't go faster and faster. If the car is cold I'm not able to get the fan speed up at all. When the car is heating up, and I press for more fan speed, it will maybe after the 4'th or 5'th push suddenly go to full speed.

The a/c works good, but I have noticed that I'm not always allowed to turn it on or off. If I press the button it will blink for a while and then stay in the positioin it was.

So basically, I have read all about the actuators and the display problems, but I haven't found anything on these last issues that I'm writing about. Maybe I'm the first

 

Your vehicle may be equipped with an Automatic Electronic Dual Climate Control System. This system can automatically adjust and control temperature output, fan speed, air delivery mode, air conditioning operation and air intake. You can use the AUTO (automatic) setting or override the automatic operation with manual control settings. The set temperature will be remembered each time you turn the ignition off and restart in the same settings. You can use the memory option to recall your settings. See “Memory” in the Index.

Digital Display

The digital display shows readings in Fahrenheit or Celsius by pressing the E/M button (English/Metric) on the Driver Information Center (DIC). When you start the vehicle, the display will show the current fan speed, air delivery mode and the driver-set temperature for approximately five seconds and then show the outside temperature.

When the system is fully in the automatic mode, the word AUTO will also appear on the display unless you are in full cold 60°F (16°C) or full hot 90°F (32°C), then the word AUTO will not display. If you have selected a manual fan speed, then the fan symbol will appear on the display. If a manual air delivery mode has been selected, the delivery mode symbol will appear on the display.

Driver Set Temperature ****

The DRIVER **** changes the temperature on the driver’s and passenger’s side of the vehicle. Turn the **** clockwise to increase the temperature and counterclockwise to decrease the temperature. Whenever you turn this ****, the temperature will be displayed for approximately five seconds along with the current fan speed and air delivery mode.

When adjusting the temperature, start with a driver-set temperature of 73°F (23°C) until you determine your comfort zone. If you choose 60°F (16°C), the system will remain at maximum cooling and will not automatically adjust fan speed or air delivery. If you choose 90°F (32°C), the system will remain at maximum heating and will not automatically adjust fan speed or air delivery. Choosing either maximum setting will not cause the system to heat or cool any faster. Turning the **** past either maximum setting has no effect on the operation of the system.

Passenger Temperature Offset

The PASSENGER **** changes the temperature on the passenger’s side of the vehicle. When the **** is in the 12 o’clock position, the passenger’s temperature is the same as the driver’s. Turn the **** clockwise for warmer air on the passenger’s side, counterclockwise for cooler air. If the driver-set temperature is set at 60°F (16°C) or
90°F (32°C), turning the passenger **** has no effect because the system is locked at a maximum setting.

Automatic Operation

Press the AUTO button to place the entire system in the automatic mode. After a five-second display of the current settings, only the word AUTO and the outside temperature will be shown on the digital display unless you are in full cold 60°F (16°C) or full hot 90°F (32°C), then the word AUTO will not display. The system will operate to achieve your comfort set temperature as quickly as possible. The AUTO control system works best with the windows up and the removable roof installed or the convertible top up.

A Typical Cold Weather Example:

Your vehicle has been parked outside overnight in cold weather below 32°F (0°C) and you have set the driver temperature at 73°F (23°C) and have selected the AUTO mode. The system will automatically adjust the temperature output to maximum heating. The fan will start at a low speed. This is to avoid blowing cold air into the vehicle. The length of the delay depends on the amount of time since the engine was last started, the outside temperature and the engine coolant temperature. As the coolant warms up, the fan speed will gradually increase. Air will flow to the floor with some air to the windshield to prevent fogging under most normal conditions.

As the interior of the vehicle warms up to your comfort set temperature, the fan speed will decrease and the temperature output may become cooler. If the interior temperature continues to warm up due to heating from the sun or outside temperature increases, the system may switch to other air delivery modes (typically DEFOG or BI-LEVEL).

A Typical Hot Weather Example:

The vehicle has been parked outside all day in hot weather above 80°F (27°C) and you have set the driver temperature at 73°F (23°C) and have selected the AUTO mode. The system will automatically adjust the temperature output to maximum cooling. The fan will start at a low speed momentarily to push the hot air to the floor of the vehicle and then go to a higher fan speed with cold airflow out of the instrument panel outlets. A small amount of airflow will continue through the lower ducts to cool the floor area.

The air intake may start in the recirculated mode for maximum cooling performance. As the interior of the vehicle cools down to your comfort set temperature, the fan speed will decrease and the temperature output may become warmer. The air intake may shift from recirculation to outside air mode. If the interior continues to cool due to a decrease in the amount of heat the vehicle is absorbing from the sun or a decrease in the outside temperature, the system could switch to other air delivery modes (typically BI-LEVEL or DEFOG).

Manual Settings

With the automatic electronic dual climate control system, there are several manual settings you can use to control the system and override the AUTO operation. You can program the fan speed, air delivery mode, air intake mode and control the air conditioning operation using these settings. The system will still determine the temperature output level based on the driver-set temperature and the passenger temperature offset.

FAN SPEED: Press the button with the fan symbol on it to manually lock in the current fan speed and to stop the automatic fan speed control. Pressing the arrows will delete AUTO from the digital display. The fan graphics with the fan speed bars will be shown. To increase the fan speed so that more air flows into the vehicle, press the UP arrow on the fan switch. To decrease the fan speed and airflow, press the DOWN arrow. The AUTO button must be pressed to return to the automatic fan control.

 

Your FAN SPEED is digitally controlled via a FAN CONTROL MODULE that is located in the passengers foot well and its attached to the under side of the air box. Just follow the fan motor pig tail and you will find the module. Its held in with three screws. The two screws in the rear of the module (that are difficult to get to) just need to be loosened as the holes in the mount bracket are SLOTED!

The module has a digital speed control circuit and they can and will fail. You can get them from some autoparts houses but they are a LOT more expensive than the non dual control system.

Use the DIC and pull up the DTCs and the HVAC DTC will give you a DTC/s and tell you what is wrong and why the actuator doesn't work.

Sometimes just clearing the DTCs and getting the actuator to cycle several times makes it work again. If the drive gear in the actuator is cracked/damaged, you will need a new actuator.

 

I think the fuse needs to be removed for a certain period of time. Also, clear the codes.