When it rains my wiper blades smear my winshield !!!My friends car does the same thing ..Wats wrong do we need to replace r blades again (they r only 6 months old )????

Try replacing the arm also. There might not be enough tension in the arm pushing on the blade.

Can really be only 1 of 2 things, your wiper blade itself it old and not resilient or the "hinge" where the wiper arm pivots is partially ceased and not keeping the blade against the window. To restore the wiper blade wipe Downy fabric softener on the rubber blade or lubricate the wiper arm pivot point.

Unplug the electrical connector at the wiper motor. Use a voltmeter to check for power and ground on the Pink and dark green wires. This setup has two relays: hi speed and low speed. If you're not getting power and ground with IGN switch on RUN and wipers turned on, then yank the relays and check for ground to the relay control coils provided by the body control module. The wiper switch acts as a signal to the BCM to provide ground to the relays. The switch doesn't actually switch power to the relays.

It is most likely ;that your car has a film of some residue on the windshield. A good cleaning could help, and I have heard people have used an glass ware cleaning solution, called Barkeepers friend, or dishwasher powder and a sponge.

a couple of thoughts:
Has your windshield just been replaced?
The sensor is up by the rear view mirror, is it plugged in all the way?
Do you have the right size wiper blades on your vehicle? (too short of a blade misses the rain sensor and does not wipe it clean)
How good are your blades? ( as above, to turn off the rain sensor the blade needs to wipe it clean)
The rain sensor works by projecting multiple inferred beams to the inside of the windshield, like a prism, they reflect back to collectors. when there is a water droplet on the outside of the windshield it changes a beams trajectory and it misses the collector thust turning on the wipers.
(yes, this all happens in that little sensor up by the rear view mirror.)
check to make sure the wiper switch is in the right position.
also....I've seen rain sensors not work properly when the hood or doors are open.
hope this helps

you can try using rain-x on the windshield. or buy the next size smaller replacement blade assembly. i.e. if you use a 22" blade install a 21" blade.

the protective clutch nut at the base of the wiper arm needs adjusting

Go back to the winshield installer, Quick fix for them.

Likely you don't have the blade arms adjusted properly. Also, make sure that the motor has a good ground or it will not "park" when turned off.

Had the same problem on my '92 and 97. on the wiper motor there is a front cover held by a center screw... remove the cover there should be a small computer circuit board... disconect and replace... the cards are known to fail and a new replacement part, not a used one. they all fail on the older models.. new one has corrected the issue with the card... hope this works;;