What Does B1608 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the illuminated entry system input. The illuminated entry system provides interior and exterior lighting when doors are unlocked or opened. The BCM monitors the input signal from door switches and detects that the circuit is not completing, suggesting a break in the wiring, a faulty switch, or a connector issue preventing proper signal transmission.
Common Causes
40%
Damaged or corroded wiring harness between door switch and BCM, often from repeated door opening/closing or water intrusion
30%
Faulty door jamb switch or door ajar switch with open internal contacts
20%
Loose or corroded connector at BCM or door switch connection points
10%
Failed Body Control Module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of all door jamb switches and wiring at each door, checking for obvious damage, corrosion, water intrusion, or disconnected connectors. Pay special attention to driver's door wiring harness in the door jamb boot area where flexing occurs.
2
Step 2: Using a digital multimeter, check continuity of the illuminated entry input circuit from each door switch connector to the BCM connector with doors open and closed. Expected reading should be near 0 ohms when door is open (switch closed) and infinite ohms when door is closed (switch open).
3
Step 3: Test each door jamb switch individually by disconnecting the switch and measuring resistance across its terminals while manually actuating the switch plunger. A functional switch should toggle between continuity (0-5 ohms) and open circuit (infinite ohms).
4
Step 4: Check for proper voltage supply at door switch connectors using multimeter; should read battery voltage (typically 12-14V) on the supply wire with ignition on. If no voltage present, trace circuit back toward BCM checking for blown fuses or open circuits.
5
Step 5: Inspect BCM connector terminals for corrosion, bent pins, or moisture intrusion. If wiring and switches test good but code persists, test BCM ground circuits for proper continuity to chassis ground (should be less than 1 ohm resistance).
6
Step 6: After repairs, clear codes and cycle all doors through open/close positions multiple times while monitoring live data for illuminated entry input status to confirm proper circuit operation and verify repair success.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the illuminated entry system input. The illuminated entry system provides interior and exterior lighting when doors are unlocked or opened. The BCM monitors the input signal from door switches and detects that the circ...
The most common cause of B1608 (Illuminated Entry Input Open Circuit) is: Damaged or corroded wiring harness between door switch and BCM, often from repeated door opening/closing or water intrusion
Typical repair costs for B1608 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or driveability. The vehicle is completely safe to drive, though interior/exterior courtesy lighting may not function when doors are opened or unlocked, which could be inconvenient in dark conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1608 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Body
System
Body Control and Lighting System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
