B1838

Step 1: Locate the battery saver relay in the under-hood or interior fuse/relay box. Visually inspect the relay and socket for corrosion, burned contacts, or physical damage. Check for bent or pushed-back pins in the socket.

Step 2: With ignition off, remove the battery saver relay and test it using a multimeter. Apply 12V and ground to the relay coil terminals and verify continuity across the switch terminals changes from open to closed. Measure coil resistance (typically 70-120 ohms).

Step 3: With relay removed and ignition on, use a multimeter to verify battery voltage is present at the power supply terminal in the relay socket. Check for ground at the ground terminal. Use a test light on the BCM control terminal while commanding relay operation via scan tool (if available) to verify BCM driver circuit function.

Step 4: If relay and socket test good but code persists, check wiring continuity between BCM connector and relay socket on the control circuit wire. Look for chafing, pinched wires, or water intrusion in harness. Measure resistance (should be less than 5 ohms).

Step 5: Clear codes, reinstall or replace relay, and monitor system operation. Verify battery saver function activates properly by leaving accessories on with key off and confirming system shuts down loads after timeout period (typically 10-20 minutes).