B1690 — Autolamp Delay Circuit Open

Is it safe to drive with B1690?

Usually safe to drive — body codes rarely affect drivability. Exceptions: exterior lighting and wipers in bad weather, and central locking faults that can leave the car unsecured.

What does OBD2 code B1690 mean?

Autolamp Delay Circuit Open (B1690): a body electrical fault affecting the body electrical system. The car is usually drivable while you plan the repair. Most often caused by body control module (BCM) fault, blown fuse or failed relay, corroded or loose connectors.

How much does it cost to fix B1690?

Replace the switch or actuator — $120–$450; BCM repair or replacement — $300–$900; Repair wiring or connectors — $80–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What are the symptoms of B1690?

Drivers most often notice: no impact on engine operation in most cases, warning light on the dashboard, the affected function (locks, windows, lighting, wipers) works intermittently or not at all.

Will B1690 clear itself?

Sometimes B1690 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

The B1690 OBD2 fault code relates to the Turn Signal / Hazard Power Feed circuit. When the circuit circuit failure, the module cannot properly monitor or control this body system.

At AIscanAuto, we help drivers quickly identify OBD2 trouble codes, understand their root causes, and find the right fix.

Symptoms

• Light not working (headlamp, turn signal, tail, or interior)
• Possible bulb warning on dashboard
• Dim or flickering lights
• Other related lamps affected

Common Causes

• Faulty component — internal damage or wear affecting Turn Signal / Hazard Power Feed
• Wiring issues — broken, corroded, or chafed wires in the circuit
• Connector problems — loose, oxidized, or moisture-damaged pins
• a general circuit failure is detected — can result from wiring faults, connector issues, or component failure
• Module input failure — rare, but the control module input stage may be defective

Step-by-Step Diagnosis

1. Scan with OBD2 tool — Confirm B1690 is active. Check for additional DTCs.
2. Visual inspection — Examine the Turn Signal / Hazard Power Feed wiring and connector for corrosion or damage.
3. Check voltage and ground — Use a multimeter to verify proper reference voltage.
4. Test component — Compare readings to factory specs. A stuck or erratic signal confirms failure.
5. Check for shorts/opens — Perform continuity tests on the wiring between the component and control module.

Repair & Solutions

• If the component is defective, replace the Turn Signal / Hazard Power Feed with an OEM or quality aftermarket part.
• Repair any damaged wiring or connectors using proper methods.
• Clear the DTC with an OBD2 scanner and test drive to verify the code does not return.
• If the code persists after component replacement, inspect the control module connector.

Related Codes

• B1687 — Lamp Air Bag Warning Indicator Circuit Short To Battery
• B1688 — Passenger Air Bag Disable Module Fault
• B1689 — Turn Signal / Hazard Power Feed Circuit Short To Battery

When your vehicle's body control module detects that the autolamp delay circuit has stopped conducting electricity as expected, it logs trouble code B1690. This diagnostic code lives in the body electrical family rather than the powertrain category, which means engine performance remains unaffected in most cases. The autolamp delay function itself controls how long your headlights or exterior lamps stay illuminated after you turn off the ignition—a convenience feature that most drivers never think about until it stops working.

An "open circuit" condition simply describes a break in the electrical path that prevents current from flowing through the autolamp delay system. B1690 gets set when the module sends a signal down this circuit and receives no response, or when readings fall outside the factory-defined acceptable range for a predetermined number of drive cycles. The stored freeze frame data captures engine speed, load, temperature, and vehicle speed at the exact moment the fault occurred, giving you a precise snapshot of conditions when the problem first appeared. This information is invaluable when chasing intermittent issues because it tells you what the car was doing when the circuit went open.

The body control module continuously monitors the autolamp delay circuit while the vehicle is running. When two consecutive good drive cycles pass without re-triggering the fault, many modules will automatically clear B1690 from memory. However, if the underlying electrical issue persists, the code returns and the warning light stays on.

Symptoms of B1690

• Check engine or body control warning light illuminates on the instrument cluster
• Headlights or parking lamps fail to stay on after the ignition is turned off
• Autolamp delay function operates inconsistently or not at all
• Other body electrical functions may work normally since the BCM isolates individual circuits
• No drivability changes—acceleration, braking, and shifting remain unaffected
• Affected function may work intermittently depending on whether the open is complete or partial
• Some vehicles may experience related body module communication codes alongside B1690

Common Causes

The most frequent culprits behind B1690 are wiring problems and connector failures:

• Blown fuse feeding the autolamp delay circuit
• Broken or chafed wire within the autolamp delay harness
• Unplugged connector, backed-out terminal pin, or heavy corrosion on connector contacts
• Internally failed autolamp delay switch or actuator module
• Loose or corroded ground connection affecting the circuit
• Wiring damage at flex points such as door jambs and tailgate hinges where wires bend repeatedly
• Faulty relay or body control module itself (less common but possible)
• Water intrusion into connectors located in wet areas of the vehicle

How to Diagnose B1690

Systematic diagnosis prevents unnecessary part replacements and keeps repair costs reasonable:

1. Connect an OBD2 scanner and verify that B1690 is stored in the body control module. Save all freeze frame data—this tells you vehicle speed, RPM, engine load, and coolant temperature when the fault first appeared.
2. Check for any manufacturer technical service bulletins (TSB) that apply to your specific make, model, and model year. Search the NHTSA database or your manufacturer's website using your VIN—some B-series codes have known fixes or software updates.
3. Perform a thorough visual inspection of the wiring harness and connectors associated with the body electrical system. Look for damaged insulation, broken strands, corrosion buildup, and any signs of previous repairs that may have been done incorrectly.
4. Use a multimeter to perform continuity testing on the autolamp delay circuit from end to end. While monitoring the reading, gently wiggle the harness at flex points—intermittent opens will show as fluctuating or infinite resistance.
5. Examine connectors at the headlamp switch, BCM, and any junction points. Pull back weatherstripping to inspect the door jamb areas where moisture and movement cause early failures.
6. Operate the autolamp delay function while observing relevant parameter IDs in live data. This confirms whether the switch input, module output, and actuator response all behave correctly.
7. Clear the code, complete a full drive cycle that replicates the freeze frame conditions, and verify that B1690 does not return. If the code reappears, the underlying electrical fault remains present.

Repair Options and Costs

Before spending money on expensive control modules, address the cheaper possibilities first. Common repair costs for B1690 (parts and labor at independent shops, USD):

• Wiring repair or connector replacement: $80–$250
• Autolamp delay switch or actuator replacement: $120–$450
• Body control module repair or replacement: $300–$900

The total cost to resolve B1690 typically falls between $80 and $900 depending on which component actually failed. An accurate diagnosis before purchasing parts always saves money—the body control module scenario represents the most expensive repair and should be your last resort after confirming the module itself is defective.

Can You Drive with B1690?

B1690 carries a short severity rating because it does not affect engine operation or safety-critical drivetrain functions. Most drivers can continue operating the vehicle normally while addressing this code at their convenience. The main safety exceptions involve exterior lighting malfunctions in low-visibility conditions and central locking failures that could leave the vehicle unsecured. Use caution and prioritize repairs if your vehicle relies heavily on the affected autolamp function for visibility or security.

Related OBD2 Codes

• B1600: PATS Ignition Key Transponder Signal Is Not Received
• B1601: PATS Received Incorrect Key-Code From Ignition Key Transponder
• B1602: PATS Received Invalid Format Of Key-Code From Ignition Key Transponder
• B1603: Lamp Anti-Theft Indicator Circuit Failure
• B1604: Lamp Anti-Theft Indicator Circuit Open
• B1605: Lamp Anti-Theft Indicator Circuit Short To Battery