2003 Ford F150 Regular Cab passenger side floor board wet at time

change master cylinder its bad internally

MOST LIKELY A VACUUM PROBLEM .. UNDER THE HOOD NEAR THE A/C RECIEVER DRYER LOCATE THE VACUUM HOSE THAT GOES INSIDE THE CAB . CHECK FOR VACUUM ON IT WITH ENGINE RUNNING. IF NO VACUUM CK THE ENGINE VACUUM HOSE HARNESS BACK TO THE ENGINE AND TO THE VACUUM RESERVOIR. . CORRECT ANY ENGINE VACUUM LEAKS FIRST. THEN CK INSIDE ON PASSENGER SIDE LOWER DASH FOR VACUUM HOSE CONNECTOR CONNECTION THERE SHOULD BE VACUUM ON BLACK HOSE .

I just commented on this same prob........check to see if the drain is clogged. That would be the A/C evaperator box and it has to drain.

If you are talking about the SRS light, the LFC ( light Flash Code ) 27 is :

Passenger Air Bag Deactivation ( PAD ) warning lamp shorted to ground

Have you done, or had any work done in the dash area as of late ?

The PAD light cannot illuminate, so the truck is reporting the code via the SRS LFC.

Start with the PAD lamp, and work you way backwards on the wiring harness, looking for a wire that has the insulation damaged, and making contact with the dash frame.
Could be right at the PAD lamp holder also.

This will take some time, but should be an easy fix.

common problem. timing chain tensioner needs to be replaced. chain has too much slack causing the noise.

They usually mount them in one of two places. First place is behind the right kick panel on the passenger side. The second place is under the seats or center console under the carpet. Check behind kick panel first since it is the easiest.

The temperature blend door actuator is located on the right side of the transmission hump under the evap. case. The floor ducts cover it.

Leak around the windshield.Have seen alot of these. If you have access to an air compressor it is pretty easy to find the leak just spray some foam window cleaner around the outside of the windshield and the hit it with air on the inside. It will blow the foam when you hit the leak. You will most likely have to have the windshield cut out and resealed and unfortunately half the time they crack when doing this.

It is an old trick when plagued by a persistant light to disconnect it, especially if it is a used vechicle just purchased.
Bill

there is a vent opening linkage for the top vents if you had removed panel for sterio install this linkage might have come loose or the wiren to electric relay to open top vents came loose

also vent doors on front of a/c vents are turned to the closed position

also quite possible the passenger blower motor compartment door in side the blower mode has something blocking entrance

also your truck might be equiped with a blower motor filter i read that these need to be changed out during normal filter replacements the filters for ford i didnt know they started using filters for a/c on reading this since 2000