* Fuse: Check your vehicle's fuse box (usually under the hood or in the passenger compartment) for a blown fuse related to the rear wiper. Your owner's manual will show you the fuse diagram and which fuse controls the rear wiper. Replace the fuse if it's blown.
* Switch: The rear wiper switch itself could be faulty. Try the switch multiple times to see if it's intermittent. If it doesn't work at all, the switch might need replacing.
* Motor: The rear wiper motor could be malfunctioning. This requires more technical expertise to diagnose and could involve testing the motor's electrical connections and the motor itself. A faulty motor usually needs replacement.
* Wiring: There might be a break or short circuit in the wiring harness leading to the rear wiper motor. This is harder to diagnose and often requires a professional to trace the wiring.
* Wiper Arm/Blade: While less likely to prevent the *motor* from running, a severely jammed wiper arm or a frozen blade could put too much strain on the motor, causing it to stop working as a safety mechanism. Try freeing up the wiper arm and replacing the blade if it's old or damaged.
* Intermittent Wiper Issue: If the rear wiper sometimes works and sometimes doesn't, this points towards a possible electrical connection issue (loose wire, corroded connector) or a failing switch.
What to do:
1. Consult your owner's manual: This will be your first and best resource for information on your specific Fiesta model's fuse box, wiring diagrams, and troubleshooting steps.
2. Check the fuse: This is the easiest and cheapest thing to check first.
3. Inspect the wiper arm and blade: Make sure they aren't frozen or severely jammed. Replace the blade if it's worn.
4. If the problem persists: Take your Fiesta to a qualified mechanic or an auto electrician. They have the tools and expertise to diagnose the problem accurately and perform the necessary repairs.
Don't attempt complex electrical repairs yourself unless you have the experience and knowledge to do so safely. Incorrect repairs can lead to further damage or even electrical shock.
