7 Common GMC Sunroof Problems [With Quick Fixes]

Sunroof adds style and ventilation to your car. The sunlight coming inside brightens the car cabin through its open top.

But this feature has many hazards, as it can quickly become a nightmare when the sunroof stops moving. 

The rainy weather can change the cabin into a pool. It’s a  hazard to the passengers, and Driving with a chipped sunroof is a risk for you.

Here are six common GMC Sunroof Problems to tell you what’s yours and the easy fixes.

GMC Sunroof Problems

GMC Sunroof Problems

1. Jammed Seal

GMC cars need the detailed cleaning of the seal and deflectors at least twice a year. The dust from the roads clogs the seal and its rail.

Hence, the sunroof won’t be able to slide smoothly on the track after some time.

Hence when you press the GMC Sunroof switch to open or close it. It would get stuck at a hard point and move. But if you won’t clean the track ever, it would ultimately stop the sunroof from moving. 

Therefore it’s better to clean the GMC Sunroof rail and track manually. Apply Grease after six months for its better working.

2. Broken Glass or Plastic Parts

The GMC Sunroof may make rattling sounds. That is annoying when you are driving and can’t determine where it’s coming from.

Often, a broken plastic part of the sunroof seal gets into the track. That needs the total replacement of the sunroof seal. Fortunately, the GMC Sunroof seal replacement parts are not expensive.

Hence if you want to replace the sunroof track using a DIY method, it would cost you $ 39 for the Track replacement. ( $ 97 if you replace the seal as well).

3. Leak In Sunroof Track

The GMC Sunroof leakage commonly occurs when your seal is broken or the drain pipe is clogged.

The drain pipe runs around the sunroof track. There is also a water tray beneath the track where the drain pipe runs along the track.

If there is a leakage, You hear the water sloshing sound around the roof, which would soak the headliner.

Ultimately the leak would begin to drain water into the car cabin. Hence You need to look for the reason for the leak and fix it with the help of tools available at the closest store.

4. Chipped Glass

A broken or chipped glass on the sunroof would be a significant hazard. The water can enter the cabin any minute the rain starts, destroying your GMC Car interior.

Not to forget that the broken glass is easy to break in thieves. Also, with the broken glass, you could not maintain the car at a specific temperature.

Hence, never leaving broken glass and repairing it as soon as possible is advisable.

5. Faulty Switch

Sometimes, the sunroof switch is dysfunctional. That conducts no current to operate the sunroof. 

You can check the sunroof switch with the help of a multimeter or a hot wire to find out if it’s the faulty switch or if the connection is not working.

6. Blown Fuse

GMC Cars’ fuse connected to the Sunroof motor controls the excessive current flow in a circuit. That prevents the sunroof motor from any damage if something goes wrong. 

So a damaged fuse can stop the current flow, and the sunroof would not operate normally when you press the switch.

Replace the fuse with a new one to solve the GMC Sunroof problem.

7. Motor Stopped Working

The sunroof motor operates a heavy-weight sunroof. Sunroof in GMC weighs around 25-35 kg. 

And if there is any kind of obstruction in the track, such as mould, rust and dust, the motor has to exert extra force to open and close the sunroof.

That puts extra strain on the sunroof motor, and it stops working if it does not respond after detailed cleaning of the motor housing and winding for rust and mud. 

Then, Unfortunately, there is no way other than replacing the sunroof motor.

How To Fix The GMC Sunroof Problems

Here are 6 DIY methods to fix the GMC Sunroof problems. 

1. Clean the Clogged Drain Pipe

The drain pipe leak is a common problem in GMC cars. The drain pipes are present along the sunroof track in the metal tray. You need to access them by opening the headliner.

Hence using a T25 screw head, you need to remove the screws on the handles to reach the drain pipe. 

Fix the Drain Pipe

Now blow compressed air in the pipe as it would remove the dust, leaves, or small stones in the drain pipe. 

You can clean the drain pipe using the fish tape wire available in any retail store. Or you can make it yourself by creating a hook of bicycle brake wire. 

The wire would clean the clogged dust and debris as you push it inside the tube. Push it further to ensure that there is no blockage.

Afterwards, make sure the pipe is not leaking in the car cabin by pouring water into the tray. 

But if the wire does not get beyond a certain point. That means it cannot get ahead, and pushing it further would damage the drain pipe.

In that case, contact the GMC Dealership to clean the drain pipe. But

Fix The Broken Seal

Sunroof Seal is a plastic piece that can wear out after some time. The cracks in the seal or the break would cause leakage in the car cabin. Mold and water that stays on the seal cause it to lose its shape.

Initially, you would see the headliner is soaked. But if the broken seal is left, the water would begin dripping into the cabin.

You need to join the broken seal with the help of a black electric liquid seal and apply it to the damaged parts of the seal. Allow it to dry as recommended in its manufacturer’s instructions.

Afterwards, run a water leak test to ensure you have covered all the parts of the broken seal.

2. Grease The Seal And Deflector

The sunroof track, seal, and deflectors in GMC cause obstruction in the smooth movement of the sunroof.

You need to clean the track to make it work like new manually. Here is the detailed method to clean the sunroof seal and deflector. 

  1. Take a clean towel and soak it in the alcohol solution (Isopropyl Alcohol) and wipe the sunroof track gently. Make sure to remove the dust entrapped in between the seal.
  1. Afterwards, apply the Silicone grease evenly on all parts, including the seal and deflector. 
  1. To spread the grease evenly, turn on the ignition and allow the sunroof to move on the track back and forth. That would apply the Silicone grease on all the areas in the sunroof track.

3. Adjust The Metal Seal

The metal seal displaces from the alignment. So when you close the sunroof, it will not close to the end. Instead, it would stop and revert from a point where the metal part pops out.

The rail track has screws that need to be tightened in its place. Therefore use a T25 head screwdriver to lose the screws on the metal parts of the GMC Sunroof track. 

Then align the metal track and tighten the screws. That would align the track in the right place.

4. Replace The Broken Sunroof Glass

Most of the time, the sunroof does not close completely. It does not flush with the end. The most common reason is broken glass in the sunroof.

Wear safety gloves and Thoroughly watch the glass of the sunroof on all sides. Use the vacuum to remove the chipped glass pieces.

Afterwards, remove the sunroof assembly using the T25 head screwdriver and the seal around it. Replace the glass with the new one.

Alternatively, take the GMC car to the expert dealership for replacement. 

5. Change Faulty Wire/Switch

The GMC sunroof wire needs to be checked with the help of a multimeter. If the multimeter shows 0-ohm resistance, the faulty wire is hindering the sunroof function.

Alternatively, remove the switch box with the help of the screwdriver and remove the connector. 

Put the hot wire in the connector’s both ends where the ground and positive wires are attached if the sunroof moves after connecting the cables. 

That would clarify that GMC Sunroof’s switch is faulty. Buy the button from a trusted GMC dealership and Replace it. 

6. Replace The Fuse

You need to access the fuse box of the GMC car to find out if that is working. The fuse box is located under the front hood.

  1. Open the hood, and you will find a box on the driver’s side of the tire in the engine compartment. 
  2. Open the fuse box by pressing the clip.
  3. The number 12 fuse in GMC Acadia is labelled with 30 amp, and in GMC Yukon, it’s labelled as 25Amp.
  4. Remove the fuse and check it with the multimeter. If it shows no resistance, then change it with the new one.

Your sunroof will start working again.

7. Replace The Motor

You can replace the sunroof motor by opening the headliner above the rear car seat. Use a T25 screwdriver to remove the screws and access the motor inside. 

Replace the new one by connecting the wires and testing if it has started working.

However, It’s better to take the GMC car to an expert mechanic to replace the sunroof motor. That would save plenty of time and effort.

How To Manually Close The GMC Sunroof 

GMC Sunroof can get stuck at a point and won’t move. That would cause trouble in the rainy weather.

Therefore, you need to close it immediately and the manual closing of the GMC sunroof would temporarily fix the issue.

You need to access the Sunroof motor behind the dome light and between the sun visors.

After opening the switchboard, you will see the round hole on the front of the sunroof motor. Which rotates when you press the switch.

You need to manually rotate this in the clockwise direction by inserting the T25 key until the sunroof is completely closed.

How Do I Reset My GMC Sunroof?

The sunroof operation is an electrical system that is interrupted when you replace the battery. A disconnection requires resetting the GMC Sunroof. 

  1. To reset the GMC Sunroof, turn the ignition on and press the close switch. The sunroof will start closing slowly.
  2. You have to close the sunroof anyway. Once it is closed, press the forward button for 10 seconds. 
  3. After 10 seconds, the sunroof will complete one open and close cycle.
  4. Afterwards, the sunroof will reset, and you can open and close the sunroof with one touch.

Frequently Asked Questions

Which GMC Has a Panoramic Sunroof?

GMC Acadia 2022, Denali Ultimate, GMC Terrain and GMC Sierra 1500 have an elegant panoramic sunroof.

Does GMC Terrain Come With a Sunroof?

Yes, GMC Terrain 2018 has a panoramic sunroof.

Final Thoughts!

You can solve all the GMC Sunroof problems yourself. Most of these are related to poor service and cleaning.

That said, if you clean the sunroof twice a year, you can avoid many problems. Consult an expert dealership if you cannot solve the sunroof issues. 

References:

GMC Water Leak Solution

How to manually close a GMC Sunroof

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