What Does B1350 Mean?
B1350 indicates the Body Control Module (BCM) has detected an abnormal short to ground in the heated rear window (backlite) relay control circuit. The BCM commands the relay to activate the rear window defroster, but current flow exceeds expected parameters due to the circuit being grounded when it shouldn't be. This prevents proper operation of the heated rear window system and may cause the relay or BCM driver circuit to be damaged if the short persists.
Common Causes
45%
Damaged or chafed wiring between BCM and heated backlite relay causing short to ground
30%
Failed heated backlite relay with internal short to ground
15%
Corroded or damaged relay socket/connector creating ground path
10%
Failed BCM with shorted relay driver circuit
Diagnostic Steps
1
Step 1: Locate the heated backlite relay in the fuse/relay panel and perform visual inspection for corrosion, melted components, or damaged relay socket. Check for moisture intrusion or burned terminals.
2
Step 2: Remove the heated backlite relay and use a digital multimeter to measure resistance between the BCM control pin at the relay socket and known good chassis ground with ignition off. Reading should be >10k ohms; low resistance (<5 ohms) confirms short to ground in wiring.
3
Step 3: If relay socket tests good, bench test the removed relay by applying 12V to coil terminals and measuring resistance across normally-open contacts. Test for continuity between any relay terminal and relay case (ground); any continuity indicates internal relay short.
4
Step 4: Inspect the wiring harness from BCM to relay socket for pinched, chafed, or damaged wires, paying special attention to areas where harness passes through body panels or near sharp edges. Use multimeter continuity test on suspect wire sections.
5
Step 5: If all wiring and relay test good, suspect BCM internal relay driver failure. Verify by checking BCM connector pins for corrosion and measuring voltage at BCM control output with relay removed; constant 12V or near-zero resistance to ground indicates failed BCM driver circuit.
6
Step 6: After repair, clear codes, cycle heated backlite on/off multiple times, and monitor for code return. Verify proper operation and check for normal current draw (typically 15-25 amps) at heated backlite grid.
Estimated Repair Cost
$75 - $650
Parts + labor, varies by vehicle and location
B1350 indicates the Body Control Module (BCM) has detected an abnormal short to ground in the heated rear window (backlite) relay control circuit. The BCM commands the relay to activate the rear window defroster, but current flow exceeds expected parameters due to the circuit being grounded when it ...
The most common cause of B1350 (Heated Backlite Relay Short To Ground) is: Damaged or chafed wiring between BCM and heated backlite relay causing short to ground
Typical repair costs for B1350 range from $75 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects rear window defrosting capability. Repair is not urgent but should be addressed for visibility during inclement weather and to prevent potential BCM driver circuit damage from prolonged short circuit condition.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1350 to identify the root cause.
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Quick Info
Category
Body
System
Body Electrical System
Difficulty
Type
Manufacturer
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