Chevy Heater Not Working: Diagnosis and Repair Guide

With winter on the way one of the most important accessories that you can have in your car is the heater. We’re going to run through a quick repair guide to help you if yours isn’t working how you’d like it to.

chevy heater dial

The Problem

There are three distinct problems that you could have that would stop you heater from working:

  1. No air blowing
  2. Blower working only on certain settings.
  3. Blowing cold air only

No Air Blowing

There is a simple fix to this problem if it’s happening to your vehicle. If you can hear the fans working and can feel a temperature difference at the vents but there’s nothing forcing the air out, then it’s quite likely that the problem will be with the cabin air filters. These can occasionally become blocked up with debris that’ll restrict the air flow through the system. Simply replace this filter and the problem should be solved.

Blower Working Only On Certain Settings

This is a much more common problem than the vehicle not blowing anything, and is typical of the blower motor resistor having failed. If this is the case then it is a 10 minute fix.  This video shows you how to replace the blower motor resistor on a 2004 Silverado and the process will be very similar depending on which model Chevy you have.

Blowing Cold Air Only

This is the most complicated of the three problems. If everything else is working correctly then the most likely cause of this is that the heater core has become blocked or has air in it and will need flushing out or that there is an issue with the thermostat.

  • The easiest way to check if your thermostat is working properly is to drive the car for a while. If the gauge on the dashboard gets up to temperature as normal then the thermostat is fine. If it doesn't register any changes then it is most likely faulty and will need replacing.
  • To check if the heater core has become blocked there is a simple method to find out. If you have your car running for a little while then check the temperature of the hoses coming out of the heater core. If one of them is much hotter than the other then there is a blockage.

With the right amount of ingenuity this problem can be fixed at home rather than taking it to a mechanic. This video shows a simple way of flushing out the system that doesn't require compressed air. Jump to the 1:23 mark for the advice.