2003-2006 INFINITI G35 Side Window Glass: Sedan vs. Coupe Fitment Guide

The #1 Mistake: Sedan and Coupe Glass Are NOT Interchangeable

The coupe has longer doors and a different roofline, meaning its frameless window glass has a unique shape and curvature. The sedan has shorter doors with full frames. This applies to front and rear door glass. Before purchasing, you must verify that the glass is from the correct body style. A part from a coupe will not fit a sedan, and vice-versa.

Symptoms of Failure

Problems with your G35's side windows usually fall into two categories: issues with the glass itself, or problems with the mechanical parts that move it. It's important to know the difference.

Symptoms of Damaged Glass

• Visible Cracks or Chips: Caused by impacts from rocks, debris, or attempted theft. While small chips can sometimes be repaired, significant cracks mean the entire pane needs replacement.
• Shattered Glass: Tempered glass is designed to shatter into many small pieces upon a forceful impact.
• Scratches: Deep scratches from worn-out window seals or debris can obstruct vision and are generally not repairable.
• Grease Streaks: Infiniti issued a Technical Service Bulletin (TSB ITB03-020) for an issue where grease from inside the door could leave marks on the glass as it was raised and lowered. The fix involves replacing the felt glass stabilizer inside the door.

Symptoms of a Failing Window Regulator or Motor

More often than not, when a G35 window malfunctions, the problem is with the window regulator (the lifting mechanism) or the motor, not the glass itself.

• Window is Slow or Struggles to Move: This is a classic sign of a dying window motor or a binding regulator.
• Grinding, Clicking, or Popping Noises: These sounds often indicate a frayed regulator cable or broken plastic guides on the track.
• Window Drops Inside the Door: This happens when the regulator cable snaps or the glass comes off its track, a common failure mode.
• Window Won't Stay Up: The window may slide down on its own over time or when the door is closed.
• Window Reverses on Its Own (Coupe Models): G35 coupes have a feature where the frameless window drops slightly when the door is opened and seals back up when closed. A known issue can cause the window to go up, hit the seal, and then reverse itself about a quarter of the way down. This often requires a window motor reset procedure.

Known Issues, TSBs, and Recalls

While there have been no safety recalls issued by the NHTSA for the side window glass or regulators on the 2003-2006 G35, there are several known issues and service bulletins.

• TSB ITB03-020: Addresses grease streaks appearing on the inside of the door glass. The solution is to replace the original glass stabilizer felt with an updated part.
• TSB ITB04-033: Pertains to 2003-2004 coupes with various window issues, including the window lowering on its own. The fix is a window motor reset procedure to re-learn the proper upper and lower limits. This procedure can often be performed by the owner.
• Common Motor Failure: The window motors on the G35 are a well-documented failure point. Owners in forums frequently discuss cleaning the motor's internal contacts as a temporary fix or replacing the motor with an aftermarket unit.

Buying a Used 2003-2006 G35 Side Window Glass

A used OEM window glass is an excellent, cost-effective option, as glass does not wear out with mileage. However, careful inspection and verification are key.

What to Check Before You Buy

1. Confirm the Body Style: This is the most critical step. Get confirmation from the seller, with a photo of the donor vehicle if possible, that the glass came from a 4-door sedan.
2. Confirm the Location: Ensure you are buying for the correct door (e.g., rear driver side). Front and rear door glass are not interchangeable.
3. Inspect for Scratches: Hold the glass up to a light source and check both sides for deep scratches that your fingernail can catch on. Minor scuffs may be acceptable, but deep scratches will be visible once installed.
4. Check for Chips and Cracks: Pay close attention to the edges of the glass, as this is where small chips and cracks can start. A damaged edge can compromise the strength of the entire pane.
5. Verify the Tint: Factory G35 glass has a slight green solar tint. Ensure the used piece matches the tint of your remaining windows. Aftermarket tint film can be removed, but you should inspect for any leftover adhesive or damage from removal.
6. Check the Plastic Clips: The glass attaches to the window regulator with plastic clips or brackets. While new glass often comes with these pre-installed, ensure the clips on a used piece are intact and not cracked.

Replacement Overview & Difficulty

• Difficulty: 3/5 (Moderate)
• Estimated Time: 1.5 - 2.5 hours
• DIY Feasible: Yes, for those comfortable with basic hand tools.

Replacing the rear door window glass is a manageable DIY project. The general steps involve:

1. Removing the interior door panel. This requires a Phillips screwdriver, a flathead, and a panel removal tool to pop the plastic clips without breaking them.
2. Carefully peeling back the plastic weather barrier.
3. Temporarily reconnecting the window switch to lower the regulator until the bolts holding the glass are accessible through service holes.
4. Unbolting the glass from the window regulator.
5. Tilting and carefully lifting the glass pane out of the top of the door frame.
6. Installation is the reverse of removal. It can be tricky to align the new glass onto the regulator by yourself, so an extra set of hands is helpful.

Cost of Replacement (2003-2006 G35 Rear Door Glass)

Frequently Asked Questions (FAQ)