Test 17: Steering Column Switch Resistance Output
- Turn ignition switch to LOCK position. Disconnect Electronic Seat Adjustment (ESA) control module harness connector No. 1. See Fig 1. Measure resistance between terminals No. 8 and 12 at ESA control module harness connector No. 1. When steering column adjustment switch is in rest position, approximately 470 ohms should exist. When steering column adjustment switch is pressed to FORWARD position, approximately 39 ohms should exist. When steering column adjustment switch is pressed to REARWARD position, approximately 16 ohms should exist. If resistance is as specified, go to next step. If resistance is not as specified, check the following as possible cause and repair as necessary:
- Check wiring. See WIRING DIAGRAMS .
- Check seat adjustment switch power supply. Perform TEST 2 under SYSTEM TESTS in POWER SEATS article.
- Replace steering column adjustment switch.
- Measure resistance between terminals No. 8 and 12 at ESA control module harness connector No. 1. When steering column adjustment switch is pressed to UP position, approximately 124 ohms should exist. When steering column adjustment switch is pressed to DOWN position, approximately 65 ohms should exist. If resistance is as specified, steering column switch resistance output is okay. If resistance is not as specified, check the following as possible cause and repair as necessary:
- Check wiring. See WIRING DIAGRAMS .
- Check seat adjustment switch power supply. Perform TEST 2 under SYSTEM TESTS in POWER SEATS article.
- Replace steering column adjustment switch.
Courtesy of MERCEDES-BENZ OF NORTH AMERICA