Beretta L4-121 2.0L (1987)
Windshield: All Technical Service Bulletins
Wiper Blades - Chattering on Windshield
Date: November 1990
Corporate Bulletin No.: 031066
CHATTERING WIPER BLADES OR BLADE WIPEABILITY
Model and Year:
ALL PASSENGER CARS AND TRUCKS
TO: ALL CHEVROLET DEALERS
Chattering and poor wipeability comments may be due to the windshield glass and/or wiper blades becoming contaminated by insect residue, dirt, road
grime, carwax etc.
Clean the windshield glass with GM # 1050011 (Bon Ami) glass cleaner or equivalent.
The glass is clean when rinse water does not "bead-up," but "sheets" across the entire glass surface. Multiple cleanings may be
required to remove all contaminants.
Clean the wiper blades by using a cloth that has been saturated with full strength washer solution and wipe vigorously. Rinse the blades with
water after cleaning.