Testing Air Bag Circuit 2 ETR (500E)
WARNING: This page is about a different car, the 1993 Mercedes-Benz 500SEL and 1993 Mercedes-Benz 500E. However, it is still accessible from the selected car via links, so may be relevant.
- This test checks resistance in deployment circuit 2 for Emergency Tensioning Retractor (ETR) seat belt circuit. Connect SRS tester to SRS Red 10-pin connector. See SRS TESTER PREPARATION . See SRS RED CONNECTOR LOCATION table under DISABLING & ACTIVATING AIR BAG SYSTEM.
- Turn ignition switch to ON position. Resistance reading should be 2-7 ohms. If resistance is 2-7 ohms, go to next step. If resistance is not 2-7 ohms, go to step 4).
- Test isolation resistance by pushing ground button on SRS tester. See Figure . Resistance should be 20,000 ohms to infinity. If resistance is as specified, go to TESTING VOLTAGE TRANSFORMER heading above. If resistance is not as specified, replace SRS wiring harness. Ensure system is functioning properly. See SYSTEM OPERATION CHECK .
- Remove passenger-side seat belt trim panel located at door rear pillar. Disconnect ETR electrical connector. Resistance reading should now read infinity. If resistance reading is less than infinity, replace SRS wiring harness. Perform system operation check to ensure system is functioning properly. See SYSTEM OPERATION CHECK .
- If resistance reading is infinity, connect jumper wire across 2-wire ETR harness connector terminals. Resistance reading should read 0-1 ohm. If reading is 0-1 ohm, replace complete ETR seat belt assembly. Perform system operation check to ensure system is functioning properly. See SYSTEM OPERATION CHECK .
- If resistance reading is not 0-1 ohm, replace SRS wiring harness. Perform system operation check to ensure system is functioning properly. See SYSTEM OPERATION CHECK .