76 Heater blower problems
Thread Starter
Intermediate
Joined: Nov 2009
Posts: 25
Likes: 0
From: Somerville Alabama
76 Heater blower problems
Recent purchased car, by my 17 year old son. The heater/air conditioner blower is very week. My son and I have replaced the blower fan motor and torn down the blower box to check for trash clogging the passage. We checked the doors/dampers and all are in good working order. I have read at Corvetteforum to replace the blower with a C4 blower. My question, before replacing the blower. Have we checked all we need to check?
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
When I put new ac part in my '76 a few years ago, it still wouldn't keep the car cool inside. I pulled the carped and lined the floor with Reflectix before laying new carpet. Also pulled the dash, and put a new foam seal kit into the dash ducts. Every seal was replaced.
Now, all the air that the blower can push, comes out the vents instead of leaking out all under the dash. And what does come out the vents, keeps the car cold no matter how long it's driven.
Now, all the air that the blower can push, comes out the vents instead of leaking out all under the dash. And what does come out the vents, keeps the car cold no matter how long it's driven.
Instructor
Joined: Sep 2009
Posts: 135
Likes: 2
From: Waterbury CT.
First you must decide weather your problem is electrical or a mechanial blockage. Start by disconnecting the power wire(orange or blue) from the blower motor. Connect a volt meter or a 12 volt test light to it. Start at low blower speed and go to medium and then high. The volt meter should be low and then go to over 12 volts on high speed. The test light will glow dim and get brighter as you go to medium and then high speed. If ok then run a seperate ground wire to the ground terminal of the motor. If the blower is getting full power then you may have a lot of dirt plugging the heater core. All air goes through the heater core even before it passes through the evaperator core. Dust,leaves and mud will stop the air flow. If you remove the blower resistor from the blower box while the fan is running you should feel the air coming out the hole. Good Luck.
Thread Starter
Intermediate
Joined: Nov 2009
Posts: 25
Likes: 0
From: Somerville Alabama
Guys, Thanks for the information. I have checked the blower motor. Getting full voltage, 12 volts DC, and seems to be good air movement from the fan. The blower motor is new, my son and I replaced it two weeks ago. My son and I tag teamed the dash tear down and pulled the heater core. Found just a small amount of dust. We pulled the heater core from the blower box to check that the air passages were not blocked and they are not. I am very puzzled by this. With the blower box on the car and the duct work,removed and the fan on high the fan creates very little air flow at the outlet of the blower box. I wish I had checked the air flow with the blower box removed.
Got any other ideas on this puzzle? Has anyone found the passage from the fan down to the blower box stopped up. Its the only thing else I can thing of.
Thanks, Tim
Got any other ideas on this puzzle? Has anyone found the passage from the fan down to the blower box stopped up. Its the only thing else I can thing of.
Thanks, Tim
