I have had a lot of rain here recently and it seems like when it rains I am getting water in the dash on the passenger side. I mash the gas and here it sloshing around or mash the brake and here it sloshing around. Where the F is it. I took the rocker trim out - dry. I pulled the cutout I made in the HVAV box from the recent blend door replacement - dry. Where is it and how do I fix it. I hear its a common problem. I do not want to get the electronics wet.

 

Id say your heater core is leaking

 

Actually, I never heard of this problem. But, I wouldn't pull trim, I'd pull the plugs in the rockers first. Can't miss them, -have to take a look though.

 

There's a sump hole passenger floor board (right front), bleeds into the rockers. You can pull the inspection covers and plugs on the rockers under the cab.

You didn't say if you running the AC, so I'll leave that out.

Also, if you park the truck under a tree (specially pines!), it can plug all runoffs under cowl. Overlaps on the cab are just siliconed in spots. Trap water there long enough, it'll find it's way in. Have to blow the debris from cowl/cab holes every now and a again. I shove a shop vac in them.

Could also be the windshield. Water sloshing in the dash is different. I mean, if it's coolant/air related, different story....it doesn't slosh so...

 

I've seen water flow down the lip right under the windshield... don't know if it would hold enough to slosh though.

 

Doesn't look like that channel would hold enough to slosh....

 

Slosh in the rockers more than likley. He'll have to pull the big plug in front and the smaller one in the rear. That's a bad spot to collect water..dats for sure.

 

All rocker plug locations are here, second pic, -

https://www.f150forum.com/f6/thinkin...2/#post5774353

The first pic shows why it's a bad spot to collect water, - rust hole at rear door bottom (rocker).

 

Checked the heater core thats not it

 

Slid The end of a long cable tie into the bottom of the door vents to make sure those channels were clear and I also shook the door real hard it's nothing in the bottom of the door so that's not it

I pulled the plastic piece from the step guard in the top of the rocker and looked inside there's nothing wet inside there I put a popsicle stick in their moved around just to make sure there was nothing wet inside there and it was dry as a bone