Appellant was stopped by police officers for failing to signal a right turn. A records check showed that he was on probation, and officers searched his vehicle, finding a gun and methamphetamine. At a 1538.5 hearing, appellant made an offer of proof that he would, through the testimony of witnesses, show that there had been no signal violation. The trial court declined to hear appellant’s evidence, holding that the probation search condition made irrelevant any illegality in the stop and detention. The appellate court here reversed for a new 1538.5 hearing. A probationer subject to a search condition retains the right to be free from an arbitrary, capricious, or harassing search. The trial court should have heard the evidence and decided if the officers properly stopped appellant for a traffic violation. If it concluded that they did not, it should have reached the issue as to whether their action was arbitrary, capricious, or harassing.