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International Automotive Technicians Network
Re: 1990 peterbilt wiring diagram
Posted to HD/Fleet Forum on 5/17/2015

There is a circuit breaker at the bottom of the fuse box that rots out. There is also the main acessory relay behind the speedometer. And lastly the big circuit breaker on the inside of the left frame rail at the front. These are the most likely cause. Good lu... Login to read more.