Positive Temperature Coefficient Heater: Echo
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Toyota Tacoma, 2002 Toyota RAV4, 2002 Toyota Prius, 2002 Toyota MR2, and 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
- Remove Positive Temperature Coefficient (PTC) heater along with heater core. See appropriate HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
- To test PTC heater for continuity, using ohmmeter, check that continuity exists between each electrical terminal and ground terminal on PTC heater. See Fig 1. Replace PTC heater if continuity does not exist between any electrical terminal and ground terminal.
- To test PTC heater resistance, remove PTC heater from heater core. Place probe end of PTC heater and thermometer in container of water. Attach ohmmeter between electrical terminals on PTC heater.
- Heat water and note that resistance is within specification in relation to temperature. See PTC HEATER RESISTANCE table. Replace PTC heater if resistance is not within specification.PTC HEATER RESISTANCE
Temperature Ohms 77°F (25°C) 4800-5200 104°F (40°C) 2550-2850 212°F (100°C) 260-340