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Home >> Ford >> 1990 >> Bronco 4.9 Y, Standard, M5OD-R2 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Test FD - Brake On/Off (Boo) Switch >> Test FD - Introduction
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Test FD - Introduction

NOTE: Perform this test when Service Code 74 or 75 is displayed during QUICK TEST.
NOTE: To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: brakelight bulb, brakelight switch, or brakelight fuse. This test is intended to diagnose a faulty BOO circuit or ECA.
Fig 1: Aerostar BOO Circuits
G90H12432
Fig 2: Bronco & "F" Series Pickup (Except 7.3L Diesel) BOO Ckts
G90J12434
Fig 3: Bronco & "F" Series 7.3L Diesel BOO Circuits
G90A12435
Fig 4: Bronco II & Ranger (Except 4.0L) BOO Circuits
G90F12430
Fig 5: Bronco II & Ranger 4.0L BOO Circuits
G90G12431
Fig 6: "E" Series Van BOO Circuits
G90I12433