2024 OH CDL Practice Test: Class A - Test 2 Based on 2024 OH CDL Handbook 10. Which of the following helps the stop light switch work? A By air pressure. B By heat. C All of the listed answers. D With oil and water. Next More 10/29 Progress 0 Errors Restart Next Next Class A - Test 2 Back to Test List Class A - Test 1 Class A - Test 3 Challenge Library 12 More OH CDL Practice Tests 3 Class A - Test 3 4 Class A - Test 4 5 Class A - Test 5 6 Class A - Test 6 7 Class A - Test 7 8 Class A - Test 8 9 Class B - Test 10 Class B - Test 2 11 Class B - Test 3 12 Class B - Test 4