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Brake Switch Sense Does Not Change On Scan Tool: Testing

NOTE: After completing any repair, perform POWERTRAIN VERIFICATION TEST VER-4  under VERIFICATION TESTS.
  1. Turn ignition on. Using scan tool, select INPUTS/OUTPUTS and monitor brake switch state. Press brake pedal several times. If scan tool displays brake switch PRESSED and RELEASED, brake light switch is okay at this time. If scan tool does not display speed control switch ON and OFF, go to next step.
  2. Using a test light connected to ground, backprobe brake light switch connector terminal No. 5 (Pink/Dark Blue wire). If test light illuminates brightly, go to next step. If test light does not illuminate, repair open in Pink/Dark Blue wire between brake light switch and fuse No. 2 (20-amp) located in fuse block. Fuse block is located behind glove compartment.
  3. Turn ignition off. Disconnect brake light switch connector. Using DVOM, measure resistance between ground terminal No. 2 (Black wire) and brake light switch connector terminal No. 5 (Pink/Dark Blue wire). See Figure . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Black wire between brake light switch and ground.
  4. Using DVOM, measure resistance between brake light switch connector terminals No. 1 and 2 (component side). See Figure . Press brake pedal while monitoring DVOM. If resistance changes from less than 5 ohms to open circuit, go to next step. If resistance does not change from less than 5 ohms to open circuit or is greater than 5 ohms, replace brake light switch. See BRAKE LIGHT SWITCH  under REMOVAL & INSTALLATION.
  5. Disconnect PCM connectors. Using DVOM, measure resistance of White/Pink wire between brake light switch connector terminal No. 1 and PCM connector C3 terminal C24. See Figure . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in White/Pink wire.
  6. Disconnect Brake Transmission Shift Interlock solenoid (BTSI). Using DVOM, measure resistance between ground and PCM connector C3 terminal C24 (White/Pink wire). If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in White/Pink wire.
  7. Reconnect brake light switch connector. Using a test light connected to ground, backprobe brake light switch connector terminal No. 6 (White/Tan wire). Press brake pedal. If test light illuminates brightly, go to next step. If test light does not illuminate, adjust brake light switch. See BRAKE LIGHT SWITCH  under ADJUSTMENTS.
  8. Turn ignition off. Disconnect brake light switch connector. Turn ignition on. Using scan tool, actuate S/C vacuum solenoid. Using a test light connected to ground, backprobe brake light switch connector terminal No. 3 (Yellow/Red wire). If test light illuminates brightly, go to next step. If test light does not illuminate, go to DTC P1595: SPEED CONTROL SOLENOID CIRCUITS & DTC P1683: SPEED CONTROL POWER RELAY CIRCUIT OR 12-VOLT DRIVER CIRCUIT  under DIAGNOSTIC TESTS.
  9. If no problems are found, replace PCM. See POWERTRAIN CONTROL MODULE under REMOVAL & INSTALLATION in BODY CONTROL MODULES - WRANGLER article.
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