rodb

Need ideas for an issue with air con and vent setting only blowing out lower heater ducts. Believe I have proper vacuum going to the actuator on the orange stripe line for the diverter door but the door is stuck. This has happened once before to this car and was freed up by someone else when the AC was converted to R134A. The car then sat again for a long period and guess what. The door is once again not working. What is the best way to get at the divertor door to try and free it up? I’ve tried feeling around the actuator under the driver side dash with no luck. Is it possible to remove the glove box or center console gauge cluster to gain access? Perhaps insert something in the upper vent. I have the Shifter Console Trim Plate removed.

7T1vette

That door has an actuating 'crank' sticking out of the plenum and a vacuum actuator attached to it. With it set in the position to "DEFROST", pull the hose off that actuator and see if it really has vacuum at the actuator. If not, it could be a heater control distribution problem. If it has vacuum, unclip the actuator link from the crank; then put hose back on to see if the actuator works. If not, replace it. If it does work, try to "exercise" the damper crank to get it moving freely. Use rust penetrant at the base of the crank in attempt to free it. If you get it moving, shoot some white lithium grease into that joint. Then reassemble and see if it works properly.

amvenne

I have the same problem with my '77. Could it be the same issue? I'm not smart enough to know if the '81 and '77 have the same concept for diverters...

rodb

Finally got the diverter working without having to pull the dash pad and center gauge cluster. What a relief! After feeling my way around under the dash trying to move anything that felt like it was related to the divertor I decided drive around for a while. I had temperature set to cold, fan on high while switching between vent, heater and defrost every few seconds. Out of the blue the unit started working. The door must have been stuck and after some nudging from the vacuum it broke loose. This took about 10 minutes. Any suggestions on possible ways to lubricate the door now that it is working again?

interpon

If like my 79..i vote on leaking duct controller

https://www.corvetteforum.com/forums...on-switch.html

rodb

Excellent suggestion. Would not have considered this w/o your post. Thank you.