Cavalier heater problems

My daughter's car heater works as long as she doesn't drive over 35 miles an hour. It only works on the last two notches when it does work. It has had a new radiator and a new thermostat put in. All of the hoses has been checked and they are working fine. Could someone please help me find the problem. It gets very cold out there.

I just learned about this web site. My wife's Cavalier's heater fan works traveling at any speed, but only on the last two settings. The first two doesn't work. I just figured the switch was bad, but a friend was on the Blazer forum and a new switch never fixed their problem.

Good Morning !

I believe that you have 2 separate problems. The first one about fan speed, there is a square box, about 2 inches by 2 inches under the glove compartment against the firewall in the bottom of the fan motor housing, this box has 4 resistors epoxied on the board. There is one resister for each speed on the fan motor setting, 2 of the resistors have burnt out. This is pretty common with the Cavalier, I will be replacing my second one in 2 years in the near future. If you are flexible, and have small tools, it can be replaced in a few minutes without have to take tooo much stuff apart.

The no heat after 35 miles an hour, you need to change the thermostat again. It is vary important that you buy one form the dealer or you get one with an extra heavy spring. NAPA has one THM 531090, works great.

I suffered the same issue, after replacing 4 thermostats I found out that there is a difference in the spring diameter. That is vary critical for these cars because of the water flow, the regular replacement thermostats with the softer springs don't hold the water as the engine picks up speed.

When you get the NAPA or the dealer one look closely at the spring.

Hope this helps
Take Care
Roy

Good Morning !

I believe that you have 2 separate problems. The first one about fan speed, there is a square box, about 2 inches by 2 inches under the glove compartment against the firewall in the bottom of the fan motor housing, this box has 4 resistors epoxied on the board. There is one resister for each speed on the fan motor setting, 2 of the resistors have burnt out. This is pretty common with the Cavalier, I will be replacing my second one in 2 years in the near future. If you are flexible, and have small tools, it can be replaced in a few minutes without have to take tooo much stuff apart.

The no heat after 35 miles an hour, you need to change the thermostat again. It is vary important that you buy one form the dealer or you get one with an extra heavy spring. NAPA has one THM 531090, works great.

I suffered the same issue, after replacing 4 thermostats I found out that there is a difference in the spring diameter. That is vary critical for these cars because of the water flow, the regular replacement thermostats with the softer springs don't hold the water as the engine picks up speed.

When you get the NAPA or the dealer one look closely at the spring.

Hope this helps
Take Care
Roy

Can some one help me out. I have the same problem regarding the fan. Can you please where I can find this in my car " under the glove compartment against the firewall in the bottom of the fan motor housing" .

Is this the part required?
http://www.autozone.com/servlet/UiBroker?UseCase=C001&UserAction=performMoreDetail&Parameters=TRUE%7C%7EBLOWER%2FHEATER+SWITCH%7C%7EN ONE%7C%7EWELLS%7C%7EBLOWER+RESISTOR+++++%7C%7EFALS E%7C%7EFALSE%7C%7E365149%7C%7E5433%7C%7EDR786%7C%7 ENONE%7C%7E%2412.99%7C%7ECHEVROLET%7C%7ECAVALIER%7 C%7E1993%7C%7ENONE%7C%7E0.147%7C%7EEA%7C%7EV
And will the resistor (switch) be noticably burned out, or is this a hit-or-miss kinda thing?

Thanks,