Troubleshooting Rear Wiper Problems: 7 Common Causes
A working rear wiper is essential for seeing the road better, especially during adverse weather conditions. If you've noticed your rear wiper not working as it should, this guide explores three common reasons behind the issue and provides practical insights into diagnosing and resolving each one.
1. Seized Wiper Arm Shaft:
- Rear wiper moves slower, struggles to move, or does not move at all.
- Unusual noise from the rear wiper area.
- There may be some noise from the rear wiper motor when activated.
A seized wiper arm shaft is a very common problem. In the beginning, the rear wiper may start moving slower and eventually seizes completely. Try lubricating the wiper arm shaft with penetrating lubricant to unseize it. The sleeve where the shaft rotates might be covered by a cap; try spraying under the cap. If it doesn't work, consider replacing the rear wiper motor assembly. Regular lubrication can prevent the wiper arm shaft from seizing in the future.
2. Failed Rear Wiper Motor:
- Rear wiper does not respond to activation.
- No movement or sound from the rear wiper area.
A malfunctioning rear wiper motor is also a common cause. Check the power supply to the motor and listen for any unusual noises when the wiper is activated. If the motor is receiving power but doesn't work or shows signs of damage, the solultion is to replace it. Replacing a rear wiper motor assembly costs from $220 to $350 or more, depending on the vehicle.
3. Blown Fuse:
- Rear wiper doesn't operate at all.
- No 12-volt power at the rear wiper motor connector when the wiper is activated.
Check the fuse related to the rear wiper in the vehicle's fuse box. One common reason for the fuse to blow is when the rear wiper is turned on while frozen to the glass, which causes a current spike. Another possible cause for a blown fuse is when the wires going to the rear wiper get shorted. The one common area where the wire can break or short is the harness that bends when the liftgate opens. If the fuse is blown, replace it with a new one of the correct amperage. If it blows again, the wires could be shorted; more diagnostics will be required. Read also: How to Check a Fuse in a Car?
4. Electrical Circuit Issues:
- Rear wiper does not move when activated.
- No sound of the wiper motor running.
- No 12-Volt power at the rear wiper connector when the rear wiper is turned on.
Check the rear wiper fuse and then check for 12-Volt power at the rear wiper connector when the switch is turned on. If the fuse is OK, and the switch works, but no power at the wiper motor connector, it's a problem with the electric circuit. One common problem is when the wires break inside the harness that bends when the liftgate opens. Inspect for visible damage. If confirmed, consider repairing or replacing the affected wiring.
5. Wiper Arm Alignment Issues:
- Rear wiper moves but doesn't clean the glass in some areas.
Misaligned Rear Wiper.
Inspect the alignment of the rear wiper arm. The arm could also be seized at the pivot point or positioned the wrong way on the shaft, as in the photo. In either case, it will not clean the area that is supposed to clean. If the pivot points are seizing, lubricate them. If the wiper arm is not positioned correctly, remove it and reposition it the way it supposed to be.
6. Faulty Wiper Switch:
- Rear wiper doesn't respond to switch activation.
- The rear wiper may work if the switch is jiggled.
Test the rear wiper switch for functionality. If the switch is faulty, it may not be sending the signal to the Body Control Module (BCM) which in turn would activate the wiper motor. If you don't have the tools or diagram to test the switch, inquire with your dealer; they can test it easily with a scan tool. Replace the switch if necessary.
7. Worn Wiper Blade:
- Rear wiper moves, but it doesn't effectively clear the windshield.
Check the condition of the rear wiper blade. If it's worn or damaged, it may not make proper contact with the windshield. Replace the wiper blade with a new blade or a new rubber refill suitable for your vehicle.
By addressing minor issues timely, you can avoid more expensive problems. If you notice that the rear wipers starts moving slower, see if it needs lubrication to prevent the motor failure.