Short Circuit in Rear Light Control Circuit
This code indicates a short circuit in the rear light control circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The rear light control circuit is sending a signal to the lights, but it’s detecting a short, meaning that the electrical path is somehow completing incorrectly. This often leads to lights either staying on constantly or not functioning at all.
What the computer is actually seeing
The vehicle's control module sees a voltage drop or excess current flow in the rear light circuit, which it interprets as a fault condition.
What a healthy reading looks like
Normal operation should show around 12-14 volts in the circuit when activated, with less than 5 amps of current flowing under standard conditions.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring harness for obvious damage or corrosion, particularly near the rear light area. If damage is found, repair or replace the affected section.
- 22. Check all rear light bulbs; ensure none are broken or corroded. Replace any failed bulbs and retest the circuit.
- 33. Measure voltage at the rear light connector with the lights activated. Expected value is 12-14 volts. If voltage is low or zero, check for broken circuits along the wiring to the module.
- 44. Use an ohmmeter to check for short circuits at the rear light connector. If resistance is low (less than 10 ohms), further diagnose for a short in the harness or components.
- 55. Check for proper functionality of any aftermarket accessories connected to the rear lighting system. Disconnect them and retest if necessary.
Common causes
- Damaged wiring harness near the rear lights
- Moisture intrusion causing corrosion
- Faulty rear light assembly or bulb
- Improper installation of aftermarket lighting or trailer wiring
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Not ideal, as rear lights may be malfunctioning, increasing the risk of accidents.
Will this code come back after clearing?
If the underlying issue isn’t repaired, the code will likely return.
What happens if I ignore this code?
Ignoring it could lead to increased safety risks and potential fines for non-functioning rear lights.
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