IMPORTANT:

1. Turn the ignition switch to the RUN position.
2. Connect a test lamp between connector C200 cavity B8 CKT 2267 (ORN) and ground.
3. Press the rear defogger switch once.

Does the test lamp light?

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Go to Step 2

Go to Step 3

1. Locate the open in CKT 1850 (BLK) between the heated outside mirrors and G203/G200.
2. If there is no open repair / replace heated outside mirrors, refer to Outside Rearview Mirror Replacement .

Is the repair complete?

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System OK

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Connect a test lamp between the HTD MIR fuse located in the underhood bussed electrical center (UBEC) and ground.

Does the test lamp light?

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Go to Step 5

Go to Step 4

1. Locate the open in CKT 1093 (PPL) between the rear window defogger grid and UBEC.
2. Repair the open.

Is the repair complete?

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System OK

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1. Ensure the test lamp is still connected at HTD MIR fuse.
2. Gain access to connector C1 at the UBEC.
3. Connect a fused jumper wire (back probe) between cavity D9 and ground.

Does the test lamp light?

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Go to Step 9

Go to Step 6

1. Disconnect the rear window defogger relay.
2. Using the correct terminal adapter from J-35616-A, connect a test lamp from cavities 85 to ground and then 30 to ground.

Does the test lamp light in both cavities?

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Go to Step 7

Go to Step 8

Replace rear window defogger relay.

Is the repair complete?

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System OK

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Locate and repair the power feed from the power distribution to the rear window defogger relay.

Is the repair complete?

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System OK

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1. Locate and repair the open in CKT 193 (WHT) or CKT 2450 (BLK).
2. If there is no open, replace rear defog switch (part of HVAC Control Module). Refer to Control Assembly Replacement .

Is the repair complete?

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System OK

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