From the looks of it, you have a leaking heater core from inside the truck and the leak is hitting the floor board and trailing down along the kick panel. Check out the diagrams (below). Please let us know what happens.
Use a shop vacuum and remove the coolant from the channel. Over time it could cause wiring damage is you do not get rid of it.
The repair requires full dash removal to access the heater core.
NOTE: If a heater core leak is suspected, the heater core must be leak tested before it is removed from the vehicle.
1. Disconnect the battery ground cable.
2. Drain the radiator.
3. Remove the instrument panel. Refer to: Body and Frame, Interior Trim, Dashboard/Instrument Panel, Service and Repair, Removal and Installation, See: Dashboard / Instrument Panel > Procedures > Removal and Installation
Check out the diagrams (below). Please let us know what happens.
Images (Click to enlarge)
Tuesday, June 1st, 2021 AT 3:18 PM