After two earlier failures, the Army yesterday canceled its third try for a successful flight test of the Pershing II missile, the heart of NATO's nuclear modernization program, because of problems in the missile's electrical circuits, according to a Pentagon spokesman.

He said some of the circuits would have to be replaced.

The latest setback for the 1,000-mile-range missile gave encouragement to Rep. Jospeh P. Addabbo (D-N.Y.), chairman of the House Appropriations subcommittee on defense, who said yesterday he "definitely will move to strike all the production money" for the Pershing II from the fiscal 1983 defense money bill, which his panel will begin marking up on Monday.

Under Addabbo's proposal, research, development and testing on the missile could continue, but production would be delayed until the Pershing II had completed its test program. As of today, the Army has committed $606 million in advanced production funds for the missile.

The Pershing II was to have been fired today at the White Sands Missile Test Range in New Mexico, but a delay was ordered after problems developed during ground tests Thursday. A spokesman at the Army Missile Command in Huntsville, Ala., said yesterday that another test date will not be set until all the missile's electrical circuits are checked at the Orlando, Fla., plant of Martin Marietta Co., prime contractor on the missile.

He said that it would be "early next week" before those checks were completed.

The first flight test of the missile in July ended 17 seconds after launch when the Pershing II exploded. On Nov. 4, its second test was halted 10 seconds from ignition when the batteries aboard the missile that provide electric power during the flight to the target failed to turn on.

One cause of the current problems, according to Capitol Hill sources, is the fact that the Pershing II is on a hurry-up schedule of 18 flight tests to meet a NATO deadline for 108 missiles to be deployed beginning in December, 1983.

The Pershing program, one source said yesterday, "is being driven by political reasons. There is no logic or reason in the way its development program is being run."

On Oct. 25, despite the fact that the missile had not had a successful flight test, the Army signed a $414 million contract with Martin Marietta for advanced production of the missile.

The Pershings, along with 464 ground-launched cruise missiles, represent the new NATO nuclear force designed to counter introduction in 1977 of Soviet SS20 missiles that now total more than 300 and can hit Western European targets from their Soviet bases. The Pentagon said yesterday a ground-launched cruise missile completed a "fully guided mission" in a flight test in Utah.

The Pershing IIs are designed to hit targets in the Soviet Union from their West German bases in less than eight minutes. For that reason, the Pershings have been a particular target for critical Soviet propaganda and are opposed by many West European peace groups.

The continuing problems with the missile have diplomatic as well as technical implications.

The new West German defense minister, Manfred Werner, told reporters here last week that "it was important to remain on time" with the Pershing II deployment "or face serious consequences."