Check PTC Heater

WARNING: This page is about a different variant/trim than selected.

Trouble symptom:

Warm air not emitted.

Trouble causes:

A/C control panel failure
PTC heater failure

Wiring diagram:

Air conditioning system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIR CONDITIONER (DIAGNOSTICS) (EXCEPT FOR HEV)>GENERAL DESCRIPTION>CAUTION .

CHECK PTC HEATER RELAY .
1. Turn the ignition switch to OFF.
2. Remove the PTC heater relay.
3. Check the PTC heater relay. Ref. to AIR CONDITIONER (HEV)>RELAY AND FUSE .
Is the check result OK?

Yes: Go to 2.

No: Replace the PTC heater relay. Ref. to AIR CONDITIONER (HEV)>RELAY AND FUSE .
CHECK HARNESS .
1. Turn the ignition switch to ON.
2. Using a tester, measure the voltage between the relay holder and chassis ground.
  Connector and terminal
  
  (B225) No. 1 (+) - Chassis ground (-):
  
  (B225) No. 3 (+) - Chassis ground (-):
  
  (B225) No. 5 (+) - Chassis ground (-):
  
  (B225) No. 7 (+) - Chassis ground (-):
  
  (B225) No. 27 (+) - Chassis ground (-):
  
  (B225) No. 29 (+) - Chassis ground (-):
Is the voltage battery voltage?

Yes: Go to 3.

No: Check the terminal main fuse and fuse No. 12 in the fuse and relay box. Check for open or short circuit in harness between relay holder and fuse.
CHECK HARNESS .
1. Turn the ignition switch to OFF.
2. Disconnect the A/C control panel connector.
3. Measure the resistance between A/C control panel connector and relay holder.
  Connector and terminal
  
  (i181) No. 12 - (B225) No. 4:
  
  (i181) No. 23 - (B225) No. 8:
  
  (i181) No. 14 - (B225) No. 30:
Is the resistance less than 10 Ω?

Yes: Go to 4.

No: Repair or replace the harness.
CHECK HARNESS .
1. Disconnect the PTC heater connector.
2. Using a tester, measure the resistance between the relay holder and PTC heater.
  Connector and terminal
  
  (B225) No. 2 - (i219) No. 2:
  
  (B225) No. 6 - (i219) No. 3:
  
  (B225) No. 28 - (i219) No. 1:
Is the resistance less than 10 Ω?

Yes: Go to 5.

No: Repair or replace the harness.
CHECK HARNESS .
Using a tester, measure the resistance between PTC heater and chassis ground.

Connector and terminal

(i220) No. 1 - Chassis ground:

(i220) No. 2 - Chassis ground:

Is the resistance less than 10 Ω?

Yes: Go to 6.

No: Repair or replace the harness.
CHECK A/C CONTROL PANEL .
1. Connect the disconnected connectors.
2. Disconnect the A/C control panel connector.
3. Short the harness connector to chassis ground.
  Connector and terminal
  
  (i181) No. 12 - Chassis ground:
  
  (i181) No. 23 - Chassis ground:
  
  (i181) No. 14 - Chassis ground:
Does PTC heater become warm?

Yes: Replace the A/C control panel. Ref. to AIR CONDITIONER (HEV)>CONTROL PANEL .

No: Replace the PTC heater. Ref. to AIR CONDITIONER (HEV)>PTC HEATER .