Q: Heater only works on high

asked by on

The heater only worked on high . I actually had this same problem with my last two cars (ford ranger p.u - dodge ram van) I put a new resistor in and the heater worked fine for about a week, and now it only works on high again. Any suggestions where to look next would be appreciated. thanks tom. b.

My car has 76200 miles.
My car has an automatic transmission.

It sounds like you may have a faulty blower motor potentially drawing too much power from the resistor causing it to burn itself up. As you know, the individual blower motor resistor inside the pack are usually wire wound and they may fail by burning out from use, and may also fail due to mechanical stresses and vibrations typically found in an automotive environment. When a blower resistor is faulty, the fan will usually operate at one speed only, usually the highest speed setting possible. Sometimes, only some of the speed settings will be faulty while others might work. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Heater only works on high

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: DSC, ABS, Handbrake Light Stays On

Based on your description of the problem, I would guess that you have a bad wheel speed sensor or a tone ring that is jammed up with rust. The tone ring is a ring on the wheel hub with slots...

Q: My car wont shift out of drive but the gear shifter is moving.

Hello. It is likely an issue with your shift linkage which connects your gear shift to the transmission. Some parts of the shift linkage are made of plastic which the components break or pop off making replacement or reassembly required....

Q: Q: Air conditioner

It sounds like you may have a faulty blower motor or blower motor relay. Occasionally, the blower motor itself will wear out or become faulty working intermittently as the brush contacts inside the motor wear out. The blower motor relay...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...