What Does C1183 Mean?
The park lamp flash relay circuit is shorted to battery voltage. The control module detects constant high voltage on the relay control line when it expects it to be low. This may cause the parking lamps to stay on continuously or flash unexpectedly. While primarily a convenience feature issue, a short to battery can cause excessive current draw and potentially blow fuses or damage wiring.
Common Causes
35%
Relay control wire shorted to a 12V source in the wiring harness
30%
Park lamp flash relay stuck closed (welded contacts)
15%
Incorrect relay installed (wrong pin configuration or internal diode)
15%
Fuse box internal short or melted terminal routing battery voltage to relay control pin
5%
Control module output driver shorted high internally
Diagnostic Steps
1
Remove the park lamp flash relay. With the relay out, measure voltage at the control pin in the socket. It should read near 0V with the parking brake not being operated. If 12V is present, there is a short to battery in the harness.
2
Inspect the relay. If contacts are welded closed (relay clicks but contacts never open), replace the relay. Use an OEM-specified relay to ensure correct pin configuration.
3
Trace the relay control wire from the fuse box back to the ABS/body control module. Look for areas where the wire may be pinched against or touching a 12V wire or terminal.
4
Check for recently installed aftermarket accessories (alarm systems, remote start, lighting) that may have tapped into the park lamp circuit and introduced a constant 12V feed.
5
If no external short is found, disconnect the control module connector and check if the voltage at the relay socket drops. If it does, the module driver is shorted internally.
Estimated Repair Cost
$20 - $200
Parts + labor, varies by vehicle and location
The park lamp flash relay circuit is shorted to battery voltage. The control module detects constant high voltage on the relay control line when it expects it to be low. This may cause the parking lamps to stay on continuously or flash unexpectedly. While primarily a convenience feature issue, a sho...
The most common cause of C1183 (Park Lamp Flash Relay Circuit Short to Battery) is: Relay control wire shorted to a 12V source in the wiring harness
Typical repair costs for C1183 range from $20 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Not a safety-critical issue. Parking lamps may be on continuously, which could drain the battery if left parked for extended periods. There is a minor risk of wiring overheating from the continuous short. Safe to drive but should be repaired to prevent battery drain.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1183 to identify the root cause.
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Quick Info
Category
Chassis
System
Parking Brake / Exterior Lighting
Difficulty
Type
Manufacturer
Recommended Tools
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