When Canadians click on their television sets, they usually tune into American programs. And the Canadian government is not pleased. The final episode of ''M*A*S*H'' got the highest ratings in the history of Canadian television. ''The Winds of War'' was almost as successful, though there was not a mention of a Canadian soldier, airman, or sailor, all of whom were in France, the Battle of Britain, and the North Atlantic. The drama showed the United States agonizing for 2 1/2 years over whether to get into the war.
So a debate has arisen over whether Canada's television and film system reflects Canadian culture - or for that matter, what Canadian culture is. The federal government has tried to define culture by subsidizing films and making tough rules for content on TV and Pay TV, new to Canada this year.
Many say the content regulations for film and TV have become a national joke. Business people eager to get a TV or Pay TV license often promise anything to be granted a license. Once in business, they say that unless the rules are changed they will go broke and put people out of work. So the rules are changed amid mild rebukes at the next session of the Canadian Radio-Television and Telecommunications Commission, the government body that sets broadcast policy and decides who gets licenses.
The government was also eager to start a Canadian-based film industry. So it opened the Canadian Film Development Corporation in 1968 to help finance films, but only if the films were judged to be ''Canadian.''
A film gets ''points'' for employing a Canadian director, producer, leading actor, and so on. If the film scores enough points, it is listed as Canadian and investors can put tax-deductible money into the project. However, critics of the system contend few investors ever get more out of their investment than the tax deduction.
A number of producers, whose work some consider questionable, set up shop and turned out a series of movies, few of which have ever made money and many of which have never even seen the light of day. An exception is ''Meatballs,'' a slapstick comedy of the ''Animal House'' school - hardly what culture czars in Ottawa had in mind. Movie rules have since been tightened.
The Canadian film industry has been centered on the National Film Board, a government-owned corporation that has problems turning out dramas with box office appeal although it has won lots of awards. The US Justice Department gave it the biggest publicity boost in recent memory when it labeled three of its films as foreign propaganda. One of them, ''If You Love This Planet,'' just won an Academy Award.
Canadian television, too, has long been dominated by the government-owned Canadian Broadcasting Corporation (CBC). The CBC has had trouble producing popular dramas and variety shows, thus the popularity here of ''M*A*S*H'' and ''Dallas.''
The biggest Canadian television success story in recent years has been CBC's news and current affairs package that goes on the air at 10 p.m. every night. The first 22 minutes, called ''The National,'' is news; the rest of the hour, ''The Journal,'' is a current affairs show with interviews similar to the MacNeil-Lehrer Report as well as short documentaries. The package attracts more than 2 million viewers, a large portion for a country of about 25 million people.
The debate surrounding the CBC is whether the television service should drop all its advertising, as the radio service did many years ago, and devote itself entirely to Canadian programming. The radio service of the CBC is distinctly Canadian, consisting of intelligent current affairs shows, serious music, and drama. It garners high ratings.
The march of technology is challenging Ottawa's attempts to control and promote Canadian culture. Communications Minister Francis Fox recently ended his futile crusade against satellite dishes that were being used to bring in American programming, especially sporting events.
This means more US programs will be beamed by satellite and cable to Canada, which has the greatest percentage of its population wired for cable TV in the world.
But Mr. Fox has not given up. The government is encouraging Canadian television producers to sell their programs abroad. They may produce something Canadians want to watch as well.