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HELP! water leak front floorboards

  • Thread starter Thread starter abbiesweet
  • Start date Start date Aug 2, 2024
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    99-04 mustang v6 firewall leak
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abbiesweet

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Aug 2, 2024
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Lebanon TN
Aug 2, 2024
#1
  • Aug 2, 2024
  • #1
Hiiii.
For a few weeks there has been quite a bit of water to drip into the front floorboards. A few days ago my bf noticed that its now causing electrical issues & overheated on the interstate yesterday, he pulled over let it sit for over an hour & was able to make it back home(he said he sat with the air on high for probably 20/30 minutes before it happened & felt that might be why). He wants to clean out & drain the water from underneath the cowel but he cant seem to find where the plugs or drain is located. I have searched EVERYWHERE online & cant find any videos or pictures showing their location on 99-04 models.. Any advice would be appreciated!
 

Mustang5L5

That is…until I whipped out my Bissell
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Feb 18, 2001
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Aug 2, 2024
#2
  • Aug 2, 2024
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There really isn't a drain for the front cowl area. Most likely the reason is the windshield is sealed poorly, or the seal is failing at the base and water running down the edges is seeping in. If it's causing issues with the wiring this is likely the case if it's dripping at the corners on all the wiring in the kick panel.

Would need more specifics to really offer any assistance but my lead suspicion would be a poorly sealed windshield, especially if it's been replaced at some point.
 
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abbiesweet

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Lebanon TN
Aug 2, 2024
#3
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Usually it doesn't start leaking into the floorboards until we make a turn so its pooling up somewhere, is there a spot we could maybe drill a hole to get all the water out before resealing the windshield?
we also replaced the relay box because it was full of water
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
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Massachusetts
Aug 2, 2024
#4
  • Aug 2, 2024
  • #4
Pass side? Drivers side? Both? Which relay box? Kinda need a little more info as to what you are seeing in terms of what is getting wet in the car.


You can try pulling the cowl panel off. Then you can use a cup of water and pour it in and go for a drive and see if you can ID where the leak is. I wouldn’t try to reseal the windshield yet.

 
Last edited: Aug 2, 2024

Noobz347

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Aug 2, 2024
#5
  • Aug 2, 2024
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It's the A/C evap box that is leaking.

Look under the hood for the A/C drain hole on the passenger side next to the transmission tunnel. Should be a rubber nipple. Carefully (so as not to poke a hole in the evap coil) poke something into that hole and clear out any debris.

It might be easier to find/spot once the A/C has been run for bit.

AC drain

My floor board, specifically the driver side gets very wet when the AC is running. Does anyone know where the AC drain tube is? I read if it gets clogged it will cause the AC to leak into the car. Just trying to rule it out or hopefully it will be the fix.
stangnet.com
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
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Massachusetts
Aug 2, 2024
#6
  • Aug 2, 2024
  • #6
Noobz347 said:
It's the A/C evap box that is leaking.
Click to expand...

Leaking ac condensation shouldn’t be dripping on any wiring though. It’s relatively clean in that area and under it. Would just be a wet pass floor area.
 
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