For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the defogger system check performed? | -- | Go to Step 2 | Go to Defogger System Check
2 |

1. Turn the ignition switch on.
2. Press and release the rear defogger switch.
3. Observe the defogger indicator lamp.

Is the defogger indicator lamp on?

--

Go to Step 3

Go to Step 13

3 | Using a test light, backprobe between the rear window defogger relay connector terminal C7 and ground. Is the test light on? | -- | Go to Step 8 | Go to Step 10
4 |

1. If the defogger on indicator lamp turns off before test is made, press and release the rear defogger switch again.
2. Using a test light, probe the rear defogger grid harness connector between CKT 293 and CKT 450.

Is the test light on?

--

Go to Step 5

Go to Step 7

5 | Repair the rear defogger grid. Refer to Grid Line Repair . Is the repair complete? | -- | Go to Defogger System Check | --
6 |

1. If the defogger on indicator lamp turns off before test is made, press and release the rear defogger switch again.
2. Using a test light, probe the rear defogger grid harness connector between CKT 293 and ground.

Is the test light on?

--

Go to Step 4

Go to Step 9

7 | Repair poor connection or open in CKT 450 between the rear defogger grid and G401. Is the repair complete? | -- | Go to Defogger System Check | --
8 | Using a test light, backprobe between the rear window defogger relay connector terminal B5 and ground. Is the test light on? | -- | Go to Step 6 | Go to Step 16
9 | Repair poor connection or open in CKT 293 between the rear window defogger relay connector terminal B5 and the rear defogger grid. Is the repair complete? | -- | Go to Defogger System Check | --
10 | Check the REAR DEFOG fuse. Is the fuse open? | -- | Go to Step 11 | Go to Step 12
11 | Repair short to ground in CKT 293 or CKT 1040. Is the repair complete? | -- | Go to Defogger System Check | --
12 | Repair poor connection or open in CKT 1040. Is the repair complete? | -- | Go to Defogger System Check | --
13 | Using a test light, backprobe between the rear window defogger relay connector terminal B7 and ground. Is the test light on? | -- | Go to Step 14 | Go to Step 17
14 |

1. Using a DMM set to measure voltage, connect by backprobing between the rear window defogger relay connector terminal C5 and ground.
2. While observing the DMM, press and release several times the rear defogger switch.

When cycling the rear defogger switch, does the DMM measure a voltage between B+ and 0.5V (or less)?

--

Go to Step 15

Go to Step 20

15 | Replace the A/C-heater control. Control Assembly Replacement Is the repair complete? | -- | Go to Defogger System Check | --
16 | Replace the rear window defogger relay. Rear Window Defogger Relay Replacement Is the repair complete? | -- | Go to Defogger System Check | --
17 | Check the HVAC/DIC/DRL/HEATED SEAT fuse. Is the fuse open? | -- | Go to Step 18 | Go to Step 19
18 | Repair short to ground in CKT 241. Is the repair complete? | -- | Go to Defogger System Check | --
19 | Repair poor connection or open in CKT 241. Is the repair complete? | -- | Go to Defogger System Check | --
20 | Does the DMM remain reading B+ (10-14V)? | -- | Go to Step 21 | Go to Step 25
21 | Check for a poor connection or open in CKT 193. Is there a poor connection or open in CKT 193? | -- | Go to Step 22 | Go to Step 23
22 | Repair poor connection or open in CKT 193. Is the repair complete? | -- | Go to Defogger System Check | --
23 | Using a test light connected to B+, backprobe the A/C-heater control:

• | C67: connector C2 terminal K.

• | CJ2: connector C1 terminal 6.

is the test light on?

--

Go to Step 15

Go to Step 24

24 | Repair poor connection or open in CKT 150 (w/C67) or CKT 850 (w/o C67). Is the repair complete? | -- | Go to Defogger System Check | --
25 | Does the DMM remain at 0.5V, or less? | -- | Go to Step 26 | Go to Step 23
26 | Check for a short to ground in CKT 193. Is there a short to ground in CKT 193? | -- | Go to Step 27 | Go to Step 15
27 | Repair short to ground in CKT 193. Is the repair complete? | -- | Go to Defogger System Check | --