Electronic climate control

[Alfonso Gomez]

My 87 Coupe is equipped with the electronic climate control. I usually use it full blast and the LED display reads "10" as the highest fan speed. The thing is that while driving the fan speed drops to about half for a while. Then it goes back to full speed. A while later it drops down. Then goes up again. It does that all the time even if I set it on "manual".
I took it to an AC shop but they had never done any work on these systems and they did not know if that was the wy it should work or not. They checked and the system has a full charge.
Is this the way it works or is something wrong?
Please help, it is hot and muggy down in PR.

 

[froggy47]

If it's not on auto, I'm sure it is supposed to stay on 10 Vacuum leak or controller problem.

 

[c4cruiser]

If you have the "Auto" button on, the fan should cycle as needed to maintain the temperature setting you selected. The system on my 92 will start with the fan at the "10" setting, but as the interior temps reach the setting I want, the fan will change speeds. It should cycle somewhat but not like you describe.

Even in the "Auto" setting, if you manually select a fan speed, the speed should stay at that setting there until the controller signals a change which would be typically be a lower speed.

I would suspect a bad controller or possibly a bad contact in the circuit board. You might want to remove the controller unit and disconnect the wiring harness. Use the eraser from a lead pencil to clean the contacts on the IC board and reinstall and see if that helps.