Q&A

 Journeyman

Possibly your heater core is beginning to leak as its located behind the glove box, have him check the coolant level when its cold to see if its low

 Technician

if it is coolant leaking out the heater core, the fluid will have a very slippery feeling when rubbed between your fingers. If it isn't slippery and instead feels like water it's due to a clogged drain that allows condensation from the A/C evaporator to escape through the firewall. Best to let a professional diagnose.

There is a grommet behind your battery in the engine compartment that leaks. It leaks into the firewall and down onto the fuse box. I found out too late and had to replace the fuse box $1200 later. The grommet needs to be filled in with sealer to keep it from ruining everything.