Accelerates when using cruise control

Cruise control wouldn’t work–repeated tries and it did. Then using it (cruise control) resulted in car (Ford Windstar) to accelerate. Mechanic has replaced switches (?) and cruise starts easily but car accelerates so cruise unuseable. Any ideas to offer to mechanic?

What year Windstar Auto or manual transmission? Any CEL’s? Have you checked for error codes?

My educated guess would be a servo.

98 windstar auto transmission. One error: Right front speed sensor coherency fault. (The ABS light has been on regularly —independent of cruise runaway maybe?) No CEL problem.

Not tried but works now. Mechanic found oil leaking down wires into control module. Cleaned module. seems to be okay??