B162E – Right low beam fault – open circuit or short to positive (Mercedes-Benz)

B162E means the right low beam headlight has an electrical fault, so your passenger-side low beam may not work. That reduces nighttime visibility and can get you pulled over. According to Mercedes-Benz factory diagnostic data, this code indicates a right low beam fault caused by an open circuit or a short to positive. This is a manufacturer-specific Mercedes-Benz body code, so the exact monitoring strategy can vary by platform and headlamp type. On a Sprinter 907, treat it as a circuit integrity problem first. Confirm the circuit failure with testing before replacing bulbs, LED modules, or control units.

B162E Quick Answer

B162E on Mercedes-Benz points to an electrical fault in the right low beam circuit. The control module sees an open circuit or a short to battery positive on that lamp output.

What Does B162E Mean?

Official definition: “Right low beam fault – open circuit or short to positive.” In plain terms, a Mercedes-Benz body/lighting controller tried to turn on the right low beam. It did not see the electrical response it expected, so it stored B162E. In practice, the right low beam may be out, intermittent, or behave oddly.

What the module is checking: the controller monitors the right low beam output circuit for electrical plausibility. It looks for a valid load and a normal voltage/current pattern when it commands the lamp on or off. Why that matters: the DTC does not prove a bad bulb or headlamp. It only narrows the fault to the right low beam circuit and its wiring, connectors, lamp electronics, and the output stage driver.

Theory of Operation

On Mercedes-Benz vehicles, the body/lighting controller supplies power to exterior lights and monitors the circuit. The module commands the right low beam on, then verifies the circuit load and output behavior. Many systems also run cold and hot bulb checks to detect opens early.

B162E sets when the controller sees an open circuit or a short to positive on the right low beam line. An open usually comes from a failed filament, damaged wiring, or a poor ground path. A short to positive happens when the lamp feed touches battery voltage where it should not. That can occur from harness chafing, water intrusion in the headlamp connector, or an internal fault in the lamp assembly electronics.

Symptoms

You will usually notice a lighting problem first, then find the stored code during diagnosis.

• Right low beam out on the passenger side with the headlight switch on
• Dash warning for exterior lamp failure or bulb-out message
• Intermittent operation where the right low beam works after cycling the switch
• Flicker on the right low beam, especially over bumps
• High beam works on the right side while the low beam fails
• Only DRL works but low beam does not, depending on headlamp design
• Repeat code returns quickly after clearing and retesting
• Heat-related change where the lamp fails after warm-up if resistance rises

Common Causes

• Open circuit in right low beam power feed: A broken feed wire prevents current flow, so the module sees no load when it commands the right low beam on.
• High resistance at the right headlamp connector: Heat, spread terminals, or corrosion increases resistance and makes lamp current too low or unstable.
• Short to positive on the controlled output: Chafed insulation or a pinched harness can tie the lamp control wire to B+, so the module detects voltage when it expects a switched output.
• Incorrect bulb or LED retrofit causing load mismatch: A non-OEM lamp load can fall outside the module’s expected current window and trigger an “open circuit” style fault.
• Fuse or power distribution fault for the right low beam circuit: A partially failed fuse element, poor fuse seating, or a power distribution connection issue can open the circuit under load.
• Ground path fault at the right headlamp assembly: A loose ground fastener or corroded ground point reduces current and creates intermittent operation that the module flags.
• Harness damage near the headlamp or radiator support: Movement and vibration at the front end often damages wiring where it flexes, leading to opens or short-to-B+ conditions.
• Moisture intrusion inside the right headlamp housing: Water intrusion can corrode terminals and create unintended voltage paths that mimic an open or a short to positive.

Diagnosis Steps

Use a scan tool that can read Mercedes-Benz body and lighting faults, plus live data and actuator tests. Have a DVOM, a fused jumper, and a test light for load checks. Back-probe pins and use a headlamp bulb or suitable load to stress the circuit. Perform voltage-drop tests under load to find high resistance.

1. Confirm DTC B162E in the vehicle’s body/lighting module memory and record freeze frame data. Focus on battery voltage, ignition state, light switch position, and any stored companion lighting or power supply DTCs. Freeze frame shows conditions when the fault set, not what happens now.
2. Perform a fast visual inspection before meter work. Check the right low beam bulb, socket, and headlamp for water, heat damage, or melting. Inspect the harness routing at the headlamp, core support, and any recent repair areas for rub-through or pinched wiring.
3. Check fuses and power distribution for the right low beam circuit before probing any control module pins. Verify the correct fuse rating and that it seats tightly. Load-test the fuse path with the low beam commanded on, since a weak connection can pass continuity but fail under load.
4. Verify the module’s power and grounds under load using voltage-drop testing. Keep the circuit operating and measure from battery negative to the module ground point. A good ground drops less than 0.1V with the load on. Repeat on the module’s B+ feed if service information shows an accessible test point.
5. Use the scan tool to command the right low beam on and off with actuator control, if available. Watch for immediate DTC reset. A hard fault in a continuously monitored lighting circuit often returns at key-on or right after a command.
6. At the right low beam connector, check for the correct power and ground behavior while the lamp is commanded on. Use a test light or a known-good load in parallel when needed. Unloaded voltage alone can mislead you, since a high resistance connection can show near battery voltage with no current flow.
7. Test for an open circuit by voltage-drop across the suspected path under load. Measure across the power feed from the fuse output to the bulb connector while commanded on. Then measure across the ground path from the bulb ground terminal to chassis ground. Excessive drop points to the exact side with resistance or an open.
8. Test for “short to positive” by checking the controlled output wire for unwanted B+ when the module commands the lamp off. Disconnect the bulb and recheck to prevent backfeed through the filament or electronics. If voltage remains, isolate sections of the harness to find where the wire contacts B+.
9. Inspect and service connectors with precision. Check terminal tension, pin fit, and signs of arcing on the right headlamp connector and any inline connectors. Repair damaged terminals rather than forcing them tighter. Apply the correct sealing steps for reassembly to prevent repeat corrosion.
10. Differentiate freeze frame from a scan tool snapshot during an intermittent concern. Use a snapshot or data log while driving or while vibrating the harness to capture the moment the fault appears. Freeze frame tells you the original set conditions, while the snapshot captures the intermittent failure live.
11. Clear codes and verify repair. Cycle ignition and command the right low beam multiple times. Confirm the code stays cleared and the lamp current behavior remains stable. Recheck for pending versus confirmed faults, since some faults need more than one drive cycle to confirm, while a true hard circuit fault returns immediately.

Professional tip: Don’t trust continuity checks on Sprinter lighting circuits. Use voltage-drop tests with the low beam commanded on and the circuit loaded. High resistance at a connector can pass continuity and still starve the lamp. When chasing “short to positive,” unplug the lamp and any related modules first to eliminate backfeed paths.

Possible Fixes

• Repair the open in the right low beam power or ground circuit after pinpointing the section with voltage-drop testing.
• Remove corrosion and restore terminal tension at the right headlamp connector or inline connectors, then seal the connection correctly.
• Repair harness chafing or pinched wiring that shorts the low beam control/output wire to B+.
• Restore proper fuse contact or repair the related power distribution connection after a load test confirms a voltage drop.
• Correct an improper bulb type or remove a retrofit that causes an out-of-range load, then retest with the correct lamp installed.
• Address moisture intrusion in the right headlamp assembly that damages terminals or creates unintended electrical paths.

Can I Still Drive With B162E?

You can usually drive a Mercedes-Benz with B162E, but you should treat it as a lighting safety issue. The code points to the right low beam circuit reporting an open circuit or a short to positive. If the right low beam does not work, you lose forward illumination and your vehicle becomes less visible. Avoid night driving, rain, fog, and poorly lit roads until you confirm operation. If the lamp stays on when it should not, the circuit may backfeed and drain the battery. That situation can also overheat wiring or a connector, so do not ignore a hot lens area or a burning smell. Verify the right low beam function before any long trip.

How Serious Is This Code?

B162E ranges from an inconvenience to a real safety concern. It feels minor if the right low beam still works and the fault sets intermittently, often from vibration or moisture at the headlamp connector. It becomes serious when the right low beam stays off, flickers, or triggers a lighting warning, because you lose usable roadway light and you can fail roadworthiness checks. The “short to positive” portion matters because it can force the circuit on or create unintended current paths. That can drain the battery or heat wiring. This code does not usually affect engine drivability, but it directly affects safe night operation and electrical reliability on a Sprinter 907 platform.

Common Misdiagnoses

Technicians often replace the right low beam bulb or LED headlamp first and stop there. That wastes time because B162E describes a circuit fault, not a confirmed lamp failure. Another common miss involves skipping load testing. A connector can pass a quick voltage check yet fail under headlamp current draw due to corrosion or a spread terminal. Shops also blame the control module too early, especially when a short-to-positive message appears. Many of those faults come from harness chafing near the headlamp, prior collision repairs, or water intrusion in the lamp area. Avoid wasted spending by verifying power feed, ground integrity, and control output behavior with the lamp commanded on.

Most Likely Fix

The most frequent confirmed repair direction involves restoring circuit integrity at the right headlamp connector or harness. That includes cleaning corrosion, repairing damaged terminals, and correcting pin fit issues that create an open under load. The next common path involves repairing a short to positive in the right low beam feed or control wiring, often from rubbed-through insulation near brackets or the radiator support. Do not treat these as certain until you prove the fault with a wiggle test, voltage drop checks under load, and a scan-tool command of the right low beam while monitoring the circuit response.

Repair Costs

Repair cost depends on whether the confirmed root cause is a sensor, wiring, connector issue, or control module problem. Verify the fault electrically before replacing parts.

Last updated: March 30, 2026