I have a 2000 Ford Taurus. It leaks water into the passenger side when the a/c is on? Has any one had this issue and fixed it?

water pump ? or a heater hose ?

The heater unit has a drain and if its blocked the condensate from the AC will run out all over the carpet ,Sorry not familar with this model have a good look and iam sure you will find it .

is the passenger side floor is damp under dash the fan motor is probably bad, some of the Taurus cars had a leak in cowl area .Ford had a hard time trying to fix it.

The ford focus and Taurus models from this period are notorious for water leakage. Unfortunately it can be from two possible causes. Lets start with easiest first. The water dam (black plastic) where the windshied meets the hood (on outside) sometimes pulls away from glass allowing water to run into the crack and then into the dash and into primarily passenger side. The fix for this is listed in a TSB by Ford and the dealer can install, for a price ofcourse, a replacement damn that helps. For my sons Taurus to diagnose if this was the true problem we put a piece of clear packing tape over the place where the dam meets the windshield making sure it was sealed to glass tightly and then waited for next rain and it was dry so that fixed it. SECOND possible cause is a bad heater core. If the wetness smells sweet like radiator fluid or sugary sweet then this is probably a coroded heater core that leaks radiator fluid into the passenger compartment. It is located in center of dash closest to passenger side. Unfortunately if this is the case it needs to be replaced and a radiator shop will charge anywhere between 250 to 500 to do the job with part included. If it is the HEATER core you should check your coolant level regularly because it operates on pressure and with a leakign heater core you can lose pressure and possible have engine overheating. Good luck

Look for moisture on the glass of the windshield, as well as the passenger side door, if thebottom seal isnt making contact on the door glass water will run in threw the door

There is a leak from your cowl area.There is a technical service bulletin to install a plastic extension onto the cowl cover so water will not leak in side. It will also damage your blower motor if you don't get it reapred.

if you can remove the plastic "cowl" section(s) at the base of the windshield and clear out any debris.sticks,dirt,acorns,mud,etc. THEN run a garden hose where the rain normally would run down and "flush"the drainage paths at each end by each fender. see if that fixes the problem. theres also a possibility that the windshield seal could be bad.

Maybe. If you have a fixed antenna on that side of the vehicle, the large rubber gromet on the wire leading into the passenger compartment may have come out, allowing lots of rain water to enter the vehicle. Happened on my 94 and flooded the passenger side.

You should try checking all of the hoses, also how long does it take for it to run out?