Air conditioning question
Thread Starter
Instructor
Joined: Jul 2010
Posts: 102
Likes: 0
Air conditioning question
The air on my 76 Vette seems to not blow the cold air out the vents very hard. I think the heat blows better . The question is... do any other people out there have the same thing happen to them with their air conditioner not blowing very hard. I have talked to several people around my area and they all say the same as me. One guy even put a new blower motor in and still the same results. I use to own a 75 back around 1978 or so and I dont remember the air not working like it should. Any ideas on this?
Safety Car
Joined: Sep 2005
Posts: 4,057
Likes: 99
From: Southeast, Tennessee
St. Jude Donor '09 thru '26
it could be that your blower motor is is j ust getting tired and the fan resistor is not getting all the power it used to to the motor. there are several posts here on replacing the fan (squirrel cage and motor) with a newer year part that has a stronger motor and a larger squirrel cage. the change out requires the addition of a spacer but it's a pretty straight forward "mod". do a search and you should find what you need in the way of information. it also could be as simple as your high speed fan isn't kicking in (could be the relay or it could be a fuse).
you should also check to make certain that in the a/c mode all the ventilation gates in the system are completely open or closed depending on which you are looking at. see if you can feel any air "leaking" out from anywhere else like the heater vent on the floor, or under the dash where the duct work pieces join, etc. that should give you a place to at least start to narrow down your problem.
you should also check to make certain that in the a/c mode all the ventilation gates in the system are completely open or closed depending on which you are looking at. see if you can feel any air "leaking" out from anywhere else like the heater vent on the floor, or under the dash where the duct work pieces join, etc. that should give you a place to at least start to narrow down your problem.
Race Director
Joined: Oct 2000
Posts: 12,652
Likes: 3,110
From: Shamong, NJ
The 76 and earlier AC system never was very good. When they switched to the modern axial compressor in late 76, the operation of the system improved considerably. Though I will say that I think that the system always blew pretty strong, they just never seem to blow as cold as in other cars of the era.
You may have a problem with the high speed blower relay, or one of the vacuum operated doors in the heater box may be stuck or not opening fully, preventing proper air flow.
You may have a problem with the high speed blower relay, or one of the vacuum operated doors in the heater box may be stuck or not opening fully, preventing proper air flow.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
There was nothing wrong with the original compressor system...other than it used more fuel to operate (less efficient than more modern system). The air blew hard and cold when new.
Your problems may lie in several areas: 1) leaves, debris collected in the A/C plenum over the years and it needs to be cleaned out; 2) vacuum system and/or hoses going to A/C-heater damper doors is not fully functional so air is not directed properly; 3) blower motor is faulty/worn out.
If you replace the blower motor, make sure you purchase a 'heavy-duty' motor. The standard replacement motors are very light duty (much less powerful than the original). Be sure to clean out the plenum prior to installing the new one.
If high speed is not working, you may have a separate fuse or relay for it (the earlier C3's had an in-line fuse located beside the brake master cylinder in the left fender).
Your problems may lie in several areas: 1) leaves, debris collected in the A/C plenum over the years and it needs to be cleaned out; 2) vacuum system and/or hoses going to A/C-heater damper doors is not fully functional so air is not directed properly; 3) blower motor is faulty/worn out.
If you replace the blower motor, make sure you purchase a 'heavy-duty' motor. The standard replacement motors are very light duty (much less powerful than the original). Be sure to clean out the plenum prior to installing the new one.
If high speed is not working, you may have a separate fuse or relay for it (the earlier C3's had an in-line fuse located beside the brake master cylinder in the left fender).
Last edited by 7T1vette; Feb 25, 2011 at 09:28 AM.
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