Brake Switch
Disconnect brake switch 6-pin connector. Using an ohmmeter, check for continuity at brake switch. See Figure . Terminals No. 1 and 2 supply brakelight sense. Terminals No. 3 and 4 supply power to vacuum servo. Terminals No. 5 and 6 supply power to dump valve. See BRAKE SWITCH CONTINUITY table. If continuity is not as specified, check brake switch adjustment. See BRAKE SWITCH under ADJUSTMENTS. If brake switch adjustment is okay, replace defective brake switch.
BRAKE SWITCH CONTINUITY
| Brake Pedal Position | Switch Plunger Position | Check Between Terminals No. | Continuity |
|---|---|---|---|
| Depressed | Extended | 1 & 2 | Yes |
| Released | Collapsed | 1 & 2 | No |
| Depressed | Extended | 3 & 4 | Yes |
| Released | Collapsed | 3 & 4 | No |
| Released | Collapsed | 5 & 6 | Yes |
| Depressed | Extended | 5 & 6 | No |