Circuit/System Testing

Single Outside Mirror Defogger Inoperative

1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate X510 or X610 inline harness connector at the A9 Outside Rearview Mirror. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal 15 and ground.
   • If 10 Ω or greater 
   1. Ignition OFF.
   2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
   • Go to next step: If less than 10 Ω 
3. Engine running, connect a test lamp between the control circuit terminal 10 and the ground circuit terminal 15.
4. Verify the test lamp turns ON when commanding the Rear Defogger On with a scan tool.
   • If the test lamp is always OFF 
   1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at the X53A Fuse Block - Rear Body.
   2. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the E17 Outside Rearview Mirror Glass.
   • Go to next step: If the test lamp turns ON 
5. Test or replace the E17 Outside Rearview Mirror Glass.

Both Outside Mirror Defogger Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate X510 or X610 inline harness connector at the appropriate A9 Outside Rearview Mirror. It may take up to 2 minutes for all vehicle systems to power down.
2. Connect a test lamp between the control circuit terminal 10 and ground.
3. Verify the test lamp turns ON and OFF when commanding the Rear Defogger On and Off with a scan tool.
   • If the lamp is always ON 
   1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at X53A Fuse Block - Rear Body, ignition ON.
   2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, refer to Rear Window Defogger Malfunction .
   • If the lamp is always OFF 
   1. Ignition OFF, remove the test lamp, disconnect the X2 harness connector at X53A Fuse Block - Rear Body, ignition ON.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance, refer to Rear Window Defogger Malfunction
   • Go to next step: If the lamp turns on and off 
4. Replace the E17 Outside Rearview Mirror Glass.