2012-2017 Fiat 500C Convertible Top Motor: Fixing a Stuck, Slow, or Dead Roof

Is It Really the Motor? Common Fiat 500C Roof Problems

Before you replace the convertible top motor, it's critical to understand that the motor itself is often not the primary point of failure in the Fiat 500C's roof system. The system's weak points are frequently the plastic guide rails and sliders that the top moves on. These components can become brittle, dry, and break over time, causing the roof to jam. When the roof jams, the motor can burn out from the strain, but replacing the motor without fixing the underlying mechanical issue will only lead to another failure.

Many top failures are misdiagnosed. A problem that seems like a dead motor could be a simple electronic glitch, a broken wire in the trunk harness, or a jammed mechanism.

Roof System Reset Procedure

1. Press and hold the 'Open' button until the roof is fully retracted.
2. Press and hold the 'Close' button. Do not release it. The roof should close completely, bypassing its normal stopping points.
3. Continue holding the 'Close' button even after the roof is fully shut. After a few seconds, the roof should automatically retract about one-third of the way and then stop.
4. Release the button. Press 'Close' again. The roof should now close completely.
5. Test the operation. The roof and trunk release should now function normally.

If the reset procedure doesn't work or you hear cracking and grinding sounds, you likely have a mechanical or motor issue.

Symptoms of a Failing Conv Top Motor

When the convertible top motor or related components fail, you may experience one or more of the following symptoms.

1. Top is Completely Unresponsive

You press the button and nothing happens. There are no sounds from the motor. This can point to a dead motor, but it's more often an electrical issue. Common causes include a blown fuse, a bad relay, a broken wire in the flexible harness near the trunk hinge, or the system needing a reset. In some cases, a faulty ambient outdoor temperature sensor can even prevent the roof from operating. A failed roof control module can also be the culprit.

2. Top Moves Slowly, Struggles, or Stops Partway

If the roof starts to move but seems weak, slow, or stops mid-cycle, it can indicate a dying motor that no longer has enough torque. However, this symptom is more frequently caused by binding in the mechanism. Dried out or broken plastic guide pieces create excessive friction, forcing the motor to work harder until it either overheats and stops, or can't overcome the resistance. This can also be a sign that the system's control module has lost its position memory, often requiring the reset procedure.

3. Grinding, Clicking, or Popping Noises During Operation

Loud mechanical noises are a clear sign of a problem. Grinding often indicates stripped gears inside the motor assembly itself. Loud cracking or popping sounds usually mean the plastic guide rails or the sliders attached to the roof have broken. When these parts break, the drive cables can come out of their tracks, causing the roof to jam and potentially damaging the motor if you continue to operate it.

4. Trunk Release and Rear Defroster Stop Working

The convertible top controls are electronically linked with the trunk latch and the rear window defroster. When the roof control module detects a fault or doesn't know the roof's exact position, it will often disable the power trunk release and the defroster as a safety measure. If your trunk suddenly stops opening with the remote or handle, a roof system fault is a likely cause.

Buying a Used 2012-2017 Fiat 500C Conv Top Motor

Given the high cost of a new OEM motor, a used unit from a recycled vehicle is a smart, cost-effective option. However, it's important to buy wisely to ensure you get a good part.

Key Inspection Points:

• Verify the Part Number: This is the most critical step. The correct OEM part number for the 2012-2017 Fiat 500C is 68140790AA. Ensure the part you are buying has this exact number. Do not rely on visual matches alone, as other motors may look similar.
• Inspect the Electrical Connector: Check the connector pins for any signs of corrosion, burning, or damage. The plastic housing should be intact and free of cracks.
• Check for Water Damage: Convertibles can be prone to leaks. Inspect the motor's housing for any chalky white residue or rust, which indicates past water intrusion that could have damaged the internal electronics.
• Ask About the Donor Vehicle: If possible, find out why the donor vehicle was taken off the road. A part from a collision-damaged car is generally a better bet than one from a flood vehicle. Knowing the mileage can also be helpful, though motor failure isn't always tied to high mileage.
• Why Used OEM is a Good Choice: For this part, there are few, if any, new aftermarket options available. A used OEM motor was built to Fiat's original standards. It offers the same fit and performance as a new dealer part at a fraction of the price.

Cost of Replacing the Conv Top Motor

The cost can vary dramatically depending on whether you only need the motor or if the entire roof mechanism requires repair.

Replacement Overview & Difficulty

Replacing only the convertible top motor is a moderately difficult job for a DIYer. The challenge comes from accessing the motor, which is located in the trunk behind several trim panels.

• Location: The motor is mounted to a bracket on the rear parcel shelf, underneath the trim.
• Access: You will need to remove the rear seat side panels and the upper trunk trim to gain access. This involves carefully prying off clips and removing several screws.
• Procedure: Once exposed, the motor is typically held on by three bolts. Disconnect the electrical harness, unbolt the old motor, and install the new one. The drive cables must be properly seated in the new motor's gear.
• Manual Operation: There is a 17mm nut on the motor assembly that allows for manual operation of the roof with a ratchet, which can be useful for diagnosis or moving a stuck top.

Frequently Asked Questions (FAQ)