It is not the heater core but rain water,near the hood hinge on the passenger side;they is a "cave in" area that trap water and in the middle they is a ruber plug that seem to leak.
silicone fix the problem for a few day,now I'm back to square 1 and the leak is back.
There is obviously a leak in either the firewall/cowl area or the window seal.
The leak is probably caused by a faulty heater core. The heater core will have to be replaced. In an emergency, the hoses can be pulled off at the firewall from inside the engine compartment and spliced.
locate the AC drain tube on the passenger side firewall ( low )and clean it out with a piece of wire, water should come out when the blockage is moved. Of course it could be your heater core in which case the leak would be coolant and you will need to replace the heater core. you can connect the two hoses going into the heater core which are also on the passenger side firewall to stop the leaking while you wait for the part.
remove hoses from firewall and make sure there is no rust or buildup on tubes. reinstall hoses and make sure hose clamps are really tight. If this doesn't work, your heater core needs to be replaced.
Wet passenger flood is caused by either a leak in the air conditioning drain line or a leak in the windshield sealant or a coolant leak coming from the heater core.
There is a drain tube that goes through the firewall and comes out under the car. Use a piece of wire to stick up there and unclog it, water will run out when you have got it.
it could be a leaky windshield or a hole in the firewall or maybe someone had changed the cabin filtre and didn't replace everything
If it is leaking under the truck it is not the heater core that is leaking. It would leak inside the vehicle on the passenger side. There is a drain tube for the A/C that is under the vehicle on the passenger side, and water from that with the A/C on is normal. If it is coolant, check the heater hose connections at the firewall. If you find that the heater core is actually leaking, replace it. No other repair is permanant.
air intake leak
On the passenger side in the wheel well behind the front wheel. Pull the front passenger side wheel and remove the wheel well cover. The charcoal canister is attached to the firewall in the wheel well. The Leak Detection pump is in front of the passenger side wheel below the air cleaner assy.
You have to determine the source of the leak then decide on how to fix it.
drain stopped up locate the drain tube on the passenger side at the firewall and use compressed air or a wire to clean it out, water should run out of it.