Heater not working
Thread Starter
Navigator
Joined: Dec 2014
Posts: 9
Likes: 1
Heater not working
Still working out a few bugs on the vette and have discovered that the heater does not blow hot air. I turn the temp up to 90 and slightly warm air comes out of the vents, with the car running at 220F I would think that the heater should be excellent. When I first turn it on it blows hot air but after about 30 seconds it is just barely warm. This leads me to believe that the heater core is plugged up. Water is not flowing freely, it just heats up the water that is in the core and that's why is works to begin with but after the water cools down it no longer works. Is there a way to flush out just the heater core? Everything else is fine. I don't want to have to replace the heater core unless I absolutely have to.
What do y'all think?
Thanks, Ranger
What do y'all think?
Thanks, Ranger
Intermediate
Joined: Jul 2014
Posts: 41
Likes: 0
From: Alabama
Still working out a few bugs on the vette and have discovered that the heater does not blow hot air. I turn the temp up to 90 and slightly warm air comes out of the vents, with the car running at 220F I would think that the heater should be excellent. When I first turn it on it blows hot air but after about 30 seconds it is just barely warm. This leads me to believe that the heater core is plugged up. Water is not flowing freely, it just heats up the water that is in the core and that's why is works to begin with but after the water cools down it no longer works. Is there a way to flush out just the heater core? Everything else is fine. I don't want to have to replace the heater core unless I absolutely have to.
What do y'all think?
Thanks, Ranger
What do y'all think?
Thanks, Ranger
Oil Producer
Joined: Apr 2014
Posts: 9,363
Likes: 2,734
agree with **** bJust finished this procedure on my 85. Blows REALLY hot now.
if that doesnt work, there is a sticky in this forum on replacing the heater core. But given u can get warmish air and its not leaking, id do flush er **** and eric the car guy b
Melting Slicks
Joined: Jan 2001
Posts: 2,996
Likes: 304
From: MOORESVILLE NC
Before you do anything else, pull the Blower Motor Control switch; shine a light into the heater core dept. to make sure you see the heater core. If you can't see the core that why your air is luke warm, you’re stuck on AC. It happens.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
I have to flush my core every year or two to keep it hot. I do it when I replace the coolant or have to open the system for any other problem. Been doing this for 10 years. Just pull off the heater hoses and flush gently with a garden hose in both directions.
I don’t think my car had a good life before I got it getting really good care.
Checking the blend door as said thru the blower control module is a quick and easy check just to make sure.
I don’t think my car had a good life before I got it getting really good care.
Checking the blend door as said thru the blower control module is a quick and easy check just to make sure.
Thread Starter
Navigator
Joined: Dec 2014
Posts: 9
Likes: 1
I checked to make sure I could see the heater core, and I could. I flushed the core out and that fixed the problem but now I have a new problem. The blower motor control module/resistor is no longer working. The blower motor will not come on at all. I checked the fuses, I ran test leads to the blower motor to make sure it works, and I checked to see if I was getting voltage to the control module. Everything checks out except I'm still not getting the blower motor to come on.
Also, I checked Oreillys and autozone and they do not even list the part. The only blower motor resistor they list is one for a manual a/c car, a traditional one that has different coils of wire for different speeds. Anyone know an auto parts store that would have the part? I found it on rock auto but I would prefer to get it locally.
Also, I checked Oreillys and autozone and they do not even list the part. The only blower motor resistor they list is one for a manual a/c car, a traditional one that has different coils of wire for different speeds. Anyone know an auto parts store that would have the part? I found it on rock auto but I would prefer to get it locally.
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Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Turn the blower on and wiggle the connector and see if it comes on. If there is no action there, turn everything off and pull the connector off the module. Look at the pins and wires to see if anything is burnt, discolored or wire not connected to pin.
You can also (and this happened to me) check out the actual blower motor. Power up the car and the blower motor and wiggle the black wires or connector going to the blower. Possible bad connection or will actually move the brushes slightly and it may start.
If something here works then at least you will know what you are dealing with.
You can also (and this happened to me) check out the actual blower motor. Power up the car and the blower motor and wiggle the black wires or connector going to the blower. Possible bad connection or will actually move the brushes slightly and it may start.
If something here works then at least you will know what you are dealing with.
7th Gear
Joined: Oct 2013
Posts: 7
Likes: 0
I have to flush my core every year or two to keep it hot. I do it when I replace the coolant or have to open the system for any other problem. Been doing this for 10 years. Just pull off the heater hoses and flush gently with a garden hose in both directions.
I don’t think my car had a good life before I got it getting really good care.
Checking the blend door as said thru the blower control module is a quick and easy check just to make sure.
I don’t think my car had a good life before I got it getting really good care.
Checking the blend door as said thru the blower control module is a quick and easy check just to make sure.
Thread Starter
Navigator
Joined: Dec 2014
Posts: 9
Likes: 1
Checked the connections at the blower motor and control module. They're all good. I used my multimeter to see if I had voltage going to the control module. I did.
When I pulled the module out and put it back in it worked fine. It was only till the next day when I went to turn the heater on that it did not work. I think it got wet and ruined it.
When I pulled the module out and put it back in it worked fine. It was only till the next day when I went to turn the heater on that it did not work. I think it got wet and ruined it.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Checked the connections at the blower motor and control module. They're all good. I used my multimeter to see if I had voltage going to the control module. I did.
When I pulled the module out and put it back in it worked fine. It was only till the next day when I went to turn the heater on that it did not work. I think it got wet and ruined it.
When I pulled the module out and put it back in it worked fine. It was only till the next day when I went to turn the heater on that it did not work. I think it got wet and ruined it.
I am out today but will have some suggestions later.
Le Mans Master
Joined: Jan 2006
Posts: 5,620
Likes: 206
From: Orlando FL
Check fuse #1 5A inside the car.
Also, there is a 30A fuse, fuse #4, for the blower under the hood in fuse block #1.
Turn key to ON (no engine) and blower to high. Measure and back probe the tan wire connector on the blower module. Maximum is 12 volts and down to 4 volts depending where it is set.
The output of the blower module is on the purple wire which will be probably be 12 volts or less depending on the fan setting which feeds the actual fan.
I wouldn't be too quick to replace anything yet when nothing is known except that it doesn't work. Make some measurements, get some data.
Also, there is a 30A fuse, fuse #4, for the blower under the hood in fuse block #1.
Turn key to ON (no engine) and blower to high. Measure and back probe the tan wire connector on the blower module. Maximum is 12 volts and down to 4 volts depending where it is set.
The output of the blower module is on the purple wire which will be probably be 12 volts or less depending on the fan setting which feeds the actual fan.
I wouldn't be too quick to replace anything yet when nothing is known except that it doesn't work. Make some measurements, get some data.