FixVault

Circuit Check

NOTE: Ensure battery is fully charged and all fuses are okay.
  1. Disconnect anti-theft control module 14-pin wiring harness connector. Anti-theft control module is located in right footwell below foot support. See Fig 1 . Ensure wiring harness connector terminals are clean and tight.
  2. Connect voltmeter positive lead to connector terminal No. 3 (Red/White wire) and negative lead to terminal No. 2 (Brown wire). If 11 volts or more are present, go to next step. If less than 11 volts are not present, repair open circuit.
  3. Disconnect anti-theft control module 8-pin wiring harness connector. Ensure wiring harness connector terminals are clean and tight. Connect voltmeter negative lead to 14-pin connector terminal No. 2 (Brown wire).
  4. Alternately connect voltmeter positive lead to 8-pin connector terminal No. 4 (Red/White wire) and No. 5 (Red/Yellow wire). If 11 volts or more are present, circuit is okay and testing is complete. If less than 11 volts are present, go to next step.
  5. Check voltage between ground and input side of auxiliary fuses. If less than 11 volts are not present, repair open circuit. If 11 volts or more are present, repair open or shorted circuit between fuse(s) and anti-theft control module 8-pin wiring harness connector.
Fig 1: Locating Anti-Theft Control Module (400E & 500E)
G93I84291Courtesy of MERCEDES-BENZ OF NORTH AMERICA