Glass, Frames and Mechanisms — 2016 workshop reference 1230

Positive Lead Measurement / Action Negative Lead Ground Rear Window Defrost Relay, socket pin 1 Ground Rear Window Defrost Relay, socket pin 3

Original table alignment retained · Scroll horizontally if needed

Glass, Frames and Mechanisms — original illustration 1, reference 1230Original colors & callouts · Select to enlarge

Glass, Frames and Mechanisms — original illustration 2, reference 1230Original colors & callouts · Select to enlarge

Are the voltages greater than 11 volts?

Yes	GO to K4
No	VERIFY the BJB fuses 9 (40A) and 66 (5A) are OK. If OK, REPAIR the circuit in question. If not OK, REFER to the Wiring Diagrams manual to identify the possible causes of the circuit short.

K4 CHECK THE FCIM (FRONT CONTROLS INTERFACE MODULE) OUTPUT

NOTICE: The following step uses a test lamp to simulate normal circuit loads. Use only a Rotunda Test Lamp (SGT27000) or 250- 300mA incandescent bulb test lamp. To avoid connector terminal damage, use the Rotunda Flex Probe kit for the test lamp probe connection to the vehicle. Do not use the test lamp probe directly on any connector. Connect:

Positive Lead	Measurement / Action	Negative Lead
Rear Window Defrost Relay, socket pin 1 Glass, Frames and Mechanisms — original illustration 3, reference 1230Original colors & callouts · Select to enlarge		Rear Window Defrost Relay, socket pin 2 Glass, Frames and Mechanisms — original illustration 4, reference 1230Original colors & callouts · Select to enlarge

Positive Lead

Measurement /

Action

Negative Lead

Rear Window Defrost Relay, socket pin 1

Glass, Frames and Mechanisms — original illustration 3, reference 1230Original colors & callouts · Select to enlarge

Rear Window Defrost Relay, socket pin 2

Glass, Frames and Mechanisms — original illustration 4, reference 1230Original colors & callouts · Select to enlarge

Activate the rear window defrost switch.

Does the test light illuminate?

Yes	GO to K5
No	GO to K6

Source reference 1230

2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.