Find your leak (it may not be the sunroof)

Before taking anything apart, confirm where the water is really coming from. The wet spot you find is usually a destination, not the source.

Start here: three quick checks

These three checks rule the sunroof in or out before you remove a single panel.

1. Rain, or air conditioning?

   If the floor only gets wet when the A/C is running and there is no puddle under the car, the water is almost certainly the air conditioning condensate drain, not the sunroof. It is clean and tracks A/C use, not rain. If the car gets wet after rain or a wash while parked, it is an outside water path, so keep going.

2. Test the sunroof drains

   Pour a cup of water into each corner of the open roof and watch it run out underneath. If every drain flows fast and clean and the cabin still gets wet, the sunroof drains are not your problem. See cleaning and testing your drains for the full method.

3. Look at the seal

   Wind noise at speed plus a visible gap where the rubber has pulled back from the glass points to a shrunken seal. That gap also floods the drains with debris, so check the drains too. See caring for your seal.

If it is none of those, trace it

When the drains flow and the seal looks fine, the water is getting in somewhere else. Find it the methodical way:

• Hose one zone at a time with someone watching inside: windshield and cowl first, then the roof and antenna, then each door, then the tailgate. Isolating zones is what tells the sources apart.
• Trace the wet track uphill. Lift the carpet and trim and follow the water back to its highest wet point. If the foam under the carpet is dry but the surface is wet, the water came from above.
• Add dye if it is stubborn. A little UV dye in the test water and a UV light will show a thin crack you cannot otherwise see.

Where it is wet, and what that points to

Other leak sources (not the sunroof)

These are the usual impostors, roughly most common first. The detail varies by make, so your vehicle guide lists the specific spots and any bulletins for your car.

• Cowl or plenum drain. Leaves clog the drains at the base of the windshield, and water overflows into the cabin air intake and the front footwell. This is the single most common leak mistaken for the sunroof.
• A/C condensate drain. A blocked evaporator drain spills into the footwell when the A/C runs. Clean water, tied to A/C use, with no puddle under the car.
• Windshield top edge. A failed urethane bond lets water down the A-pillar onto the dash and front floor. Press the glass from inside; any movement points to the bond.
• Roof antenna base. A cracked antenna seal drips onto electronics in the headliner. It often shows up first as electrical faults (radio, GPS, or SOS warnings) after rain or a wash, with a damp headliner.
• Tail light and rear lamp gaskets. A dried lamp gasket lets water into the trunk or spare wheel well, common on wagons and SUVs where the roof funnels water onto the lamp tops.
• Door vapor barrier. The plastic membrane behind the door card peels at the bottom, so water that should drain out the door gets into the cabin. Usually a wet rear footwell or door sill.
• Liftgate seal and third brake light. On SUVs, a hardened liftgate weatherstrip or a leaking roof-spoiler brake light lets water into the cargo area.
• Body seam sealer. On older cars the factory sealer over welded seams cracks and opens a path along a body seam, often into the trunk floor or spare well.
• Heater core (a mimic, not a leak). A wet footwell with an oily film and a sweet smell is engine coolant, not rainwater. That one is a repair, not a drain to clear.