Heating problem

[dusdem]

I press the heater switch on the dash and the blower motor does not come on. When I press the a/c switch the a/c comes on. Are there separate blower motors ?

 

[g413]

There is only one blower motor, but when you go into heating, the circuit will go a through a resistor to slow the motor down. You say the A/C works, but does it work on all 3 fan speeds?

What year and model of your car?

 

[dusdem]

There is only one blower motor, but when you go into heating, the circuit will go a through a resistor to slow the motor down. You say the A/C works, but does it work on all 3 fan speeds?

What year and model of your car?

 

[dusdem]

There is only one blower motor, but when you go into heating, the circuit will go a through a resistor to slow the motor down. You say the A/C works, but does it work on all 3 fan speeds?

What year and model of your car?

 

[dusdem]

What year and model of your car?

Yes, the fan works on all 3 speeds with the a/c. 1974 Plymouth Valiant 318. I can hear something engage when I press the heater. I guess its the vacuum.

 

[g413]

I have not actually gotten into one of these switches, but I believe when you press the heat button, it should complete an electrical circuit and open a port to some vacuum actuators. It sounds like the vacuum portion is working, but maybe not the electrical switch. I think the continuity of that switch should be one of the first things you look at. I wish I had a better electrical diagram to help you.

 

[BillGrissom]

The only thing I can think is that your electric-vacuum 5-button push-button switch is bad. Replacements cost ~$100. There is a good post w/ photos on opening up one and restoring it. After it melted in my 69 Dart, along w/ the L-M-H blower switch, I added a relay on the blower high position to route that high current around both switches. If not, they all melt eventually and these parts are getting scarce. At that time (~1990), a new switch was ~$20.

 

[RedFish]

The only thing I can think is that your electric-vacuum 5-button push-button switch is bad. Replacements cost ~$100. There is a good post w/ photos on opening up one and restoring it. After it melted in my 69 Dart, along w/ the L-M-H blower switch, I added a relay on the blower high position to route that high current around both switches. If not, they all melt eventually and these parts are getting scarce. At that time (~1990), a new switch was ~$20.

A push button climate controller after 72 model is greek to me. 73 and up should be the 3 lever controller ( as far as I know ).
Both types do have a vacuum + electric switch block behind the fascia if that helps.

 

[BillGrissom]

Sorry, I don't know73+ cars. I have seen the 5-button switches still available. In A-bodies, I think those only came in factory-air cars, w/ just manual cable controls in non-AC cars. Others, like my 65 Newport had the push-button switch in non-AC, but w/ only 4 buttons. Long-ago I adapted a 5-button switch to my Newport since all that was available. Regardless the "relay for blower-high" is a useful mod in any car, as I also did to my 1980's M-B cars which also melt climate switches (and blower fuse-holder). Probably around the 1990's, manufacturer's were nice and designed-in relays. Our 1960's cars were designed to last just 3 years, when most original owners traded them in.