Notes On Intermittents

Check switch for proper adjustment. Check for intermittent open circuit on circuits No. 86 and 420 from brake switches to ECM. Turn cruise On/Off switch off and manipulate wiring for circuit. No. 420. If ECM input EI71 jumps from "HI" to "LO", repair intermittent connection in circuit No. 86. If the 15-amp or 3-amp ECS fuse is being blown intermittently, check circuits No. 86 and 420 for intermittent shorts to ground.

NOTE: For diagnostic chart, see Fig 1 . For circuit identification, see Fig 2 .

Fig 1: Identifying ECM Input EI71: Brake Switch Flow Chart

Courtesy of GENERAL MOTORS CORP.

Fig 2: Identifying ECM Input EI71: Brake Switch Flow Chart Circuit

Courtesy of GENERAL MOTORS CORP.