I have a Buick Regal and the heat was only working on high. Now it is not working at all. What is the problem?

Question

the lights also go on and off while I am driving. Its a 1998

Answer 1

Heater fan speed is controlled by three things--the dash switch, the high speed by a relay and the lower speeds by a resistor. If you had no low speeds but high, then the resistor is probably bad....when the high speed failed, it was the relay going out. Could also be the dash switch itself that is bad. The resistor and relay are usually under the hood by the firewall ductwork or under the dash attached to the a/c ductwork. A shop manual like Chilton or Haynes from a parts store should show their location and what they look like. Get an electrical test light and with ignition on and fan switch on any of the lower speeds,test for power at the resistor and with switch on high speed, test relay---if no power coming in, replace. If you have power, then it's probably the dash switch is bad.
Lights going on and off sounds like a bad or intermittent ground problem...check a wiring diagram for a detail of the circuit or check for loose screws at ground connections.
Wirediagram.com

Answer 2

while all three of these answers or great and possible for this problem, i agree with the last answer regarding the resistors. Since the heater was WORKING but only on a specific setting, that would point toward a malfunction in the regulation department. Since the heater is no longer working at all, you should head down to an autozone, kragen, pep boys, etc. pick up one of the car manuals for your vehicle and see what it shows you on the heating system. You are probably looking at replacing a blower motor once the resistors went,,, good luck!

Answer 3

And going along with the first two answers, if the air is still coming out of the dash but only when the blower switch is turned to high, the "blower motor resistors" could be burned out which provide the other blower speeds. Make sure you check the coolant level in both the radiator and the overflow reservoir bottle. Wait until the engine cools.

Answer 4

In GM cars, when the heater stops working, it is a strong indication that you are low on engine coolant. Your light switch with DRL is a separate problem.

Answer 5

Another possibility, there is an interior fan that blows the hot or cold air into the interior of the car and sometimes they fail. Happened on two cars for me. If the ac and vent aren't blowing air too, it would be that.

Answer 6

suzie is in all probability marvelous...as for the different answer,s I don,t think of they observed which you stated warmth besides as a/c....& your thermostat won't have an effect on blower velocity.