Glasgow Sheriff Court was told that Gary Cryans drove a patrol car to a secluded golf course, where he parked the vehicle and made a move on his colleague.
The woman, who cannot be named for legal reasons, told the court she pushed him off and questioned his actions, but that he said nothing and drove away.
She was giving evidence at Cryans' trial, where he denies nine charges of sexual assault on colleagues and one charge of breach of the peace.
Referring to the alleged incident in 2008, procurator fiscal depute Laura Greer asked the woman what happened.
She answered: "We just parked up at the golf course one time and he tried to kiss me."
The woman told the jury she pushed Cryans off and asked what he was doing.
Miss Greer asked her if she could see anyone and she said "there was no-one else" adding that it was "pitch black".
She was asked if it was normal to park there and replied that it was not.
The witness said Cryans sometimes also parked in an industrial estate near a main road to have a break from driving when there were no calls to answer.
The woman, who is not working just now, was asked how the alleged incident made her feel and she said "uncomfortable".
She said she did not report it to the sergeant because she did not want to make an issue of it and did not feel comfortable reporting it.
The court was told that on other occasions the pair would chat in the car, although nothing untoward was said, and that Cryans told her he was not getting on with his wife.
She described Cryans, of Uddingston, as being a good police officer and good to work with, but said he was in her personal space too often.
She told the court: "When he was speaking to you he had to be right beside you.
"Also, if he was walking past he would touch your arm."
Cryans denies the charges and has lodged a special defence of consent on five charges of assault.
The trial continues.