B3890

Trailer Backup Lamps Circuit

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$22–111 (est.)

Symptoms

Trailer tail lights do not work
Trailer rear lights flashing
Error message on the dashboard

Causes

Broken or damaged wiring harness
Poor contact in connectors
Rear light relay malfunction
Problems with the trailer control module

How to Fix

Check the integrity of the trailer wiring harness
Inspect connectors for oxidation or damage
Check the taillight relay
Diagnose the trailer control module

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