PTC Heater Components (Heating and ventilation)

PTC Heater Components

1 Grommet 2 Electrical connectors 3 Earth eyelet 4 Radiator fins

5 Thermistor element 6 Frame 7 End cover 8 Silicone cap

Heater Switch The heater switch controls when the PTC operates. The switch is installed on the rear of the heater control panel and is operated by the spindle of the temperature control knob.

When the temperature control knob is selected in the cold to warm range, i.e. less than approximately 1 o'clock, the heater switch is open and the PTC heater is off. When the temperature control knob is selected in the warm to hot range, i.e. approximately 1 o'clock and above, the heater switch is closed and the PTC heater is on.

Relays A power relay and a control relay control the switching of power to the PTC heater. The power relay is installed on the engine bulkhead behind the engine compartment fusebox and is operated by the control relay. The control relay is installed at the side of the E-box and is operated by the heater switch.

Link Harness and Fuses The link harness interconnects the PTC heater system components and connects the system to the main harness. The harness is routed from the RH side of the heater assembly, through the engine bulkhead into the plenum, then along the plenum and into the rear right corner of the engine compartment. Grommets protect the link harness where it passes through the engine bulkhead and the front wall of the plenum.

An 80 A in-line fuse is incorporated into the link harness to protect the power feed from the battery to the power relay. Three 30 A fuses, in a fuse holder alongside the control relay, protect the individual power feeds from the power relay to the PTC heater.