Ferdi

This has been an intermittent problem for awhile, which now seems permanent. First, the Electronic Control Head lights for the HVAC in the dash started to flicker. Pushing a button or two allowed the green temp numerals, and yellow button lights to again become stable and the AC worked. Now, while the lights will return, the blower/fan will not blow air. The AC under the hood responds to all the dash controls, turning off and on (the compressor) as it should. P.S. the entire AC under the hood was replaced within the last 10,000 miles (compressor, dryer, etc). The AC hoses under the hood are ice cold. I have the automatic climate control unit version. Where should I start looking? I can handle just about any type of work on an automobile. Thanks, Alex

AGENT 86

Diagnosis for blower is in here >> http://members.shaw.ca/dankai/HVAC%20Electrical.pdf

Rich Silvestris

Do everything 86 tells you to do, and along the way check the connectors at the blower module (atop the evaporator housing). The wiring to the connector takes a tight turn there to get to the connector. I had a similar problem on my 87. It turned out that one of the contacts in one of the connectors had been pulled open and was not holding tight on the blade of the module. I added a little solder lump on the connector contact to increase the pressure on the blade, and all has been well since. It's a long shot, but maybe....

Ferdi

Thanks folks. My first problem is that I cannot get the heater control module in the dash to enter the diagnostic mode. With the ignition key on, and the care not running, I hold down the rear defrost button (for the rear window defroster) and while holding it down, then momentarily press the manual temp up button, and the display remains showing the number 10. It never displays a number preceeded by a minus sign. Maybe I am doing something out of order. Advice? I am going to try the electrical issue suggestion on the top of the heater evaporator housing. I vaguely remember that years ago when rooting around with the unit's connectors that the A/C started to work. Good thoughts. I am at a friends for awhile so am without my tools and shop manual, but her neighbor was able to let me have his digital multi-meter. I really appreciate the prompt replies. I have moved from Georgia to Florida and am looking to see if there is a local Corvette group to hang with.

Alex

AGENT 86

Don't bother with trying to get into diagnostic mode. Start with the voltage tests, page 64-2.

Ferdi

Yep. Going to follow your advice. Heading home Monday to the comfort of my own tools and facilities. At least I will have shade in the garage from the 98 degree weather. Funny how the heater went out in the winter, and the A/C in the summer.

Ferdi

Well! Got home to the safety of my garage and tools and dug in to my heater issue. I can say that the problem is solved. I managed to get my wiring traced to a faulty wire in the heater blower motor. I could have taken the blower apart and repaired it, but decided to give myself a treat in the hot weather, and just put in a new blower motor. Never did find out why my heater control module was blinking on and off and blacking out, but it hasn't done so since installing the new motor. Thanks for all your help and guidance.

pmihaltian

Where did you find your new blower motor? Can you post a photo of it?

Ferdi

The new blower motor was purchased at Auto Zone. I didn't know what I would find, but it was identical save for two extra holes in theounting case. It was not available at the first store, but they automatically checked their computer and found one on stock 7 miles away at another of their stores. $40 plus tax. It fit perfectly and works great. Bolt pattern perfect. I can take a photo later as I forgot to take my camera with me. Clarification - the loose connection was within the motor housing, not at the motor control on top of the evaporator housing.