phildirt

Issue is resolved. There is a pressure switch outboard and forward from the treadle/ foot pedal valve. Corrosion from Pennsylvania salt, calcium, beet juice and other evil chemicals. Required removal of primary fuel filter and fuel lines, 3 air lines to access. Thanks for input.

Thanks for the response. This apparently is set up differently. There are two 14 post terminal strips on the left side of the firewall under the hood. On the inner strip posts 4, 5, and 6 are stop, tail and turn signals for the truck - they all work on the truck. On the same strip posts 7, 8, 9, 11, 12, 13, and 14 go to a 7 wire trailer cable that goes to a junction box on the back of the sleeper and then to the trailer plug. #14 is for the trailer stop lights and it goes somewhere to get its voltage- it shows zero voltage from the foot valve, 12 volts from either the yellow or blue air valves. There are no electrical connections coming out of the foot pedal treadle air valve.

I have no trailer brake lights from the foot pedal. Normal brake lights on the trailer with the maxi brake (yellow) button and the service brake (blue) button. Truck brake lights work normally from both foot pedal and both buttons. The issue shows up at both the trailer plug and the wiring terminal strip on the left hand side of the firewall (terminal # 14). A jumper from terminal # 6 to terminal # 14 and everything is ok. The wiring diagram shows a "trailer stop lamp sw" - feeding to terminal 14. Where is that switch located? Is it part of the service brake (blue) dash button?

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Sold. Deleted

Not really sure what you are asking- This is the book you need if you are planning to change out the synchronizer in the truck.

2907 lbs, with clutch and air compressor, no oil, water, starter, fan or alternator

https://www.macktrucks.com/about-mack/museum/trucktoberfest/ You can call and register.

ET673-260 with 188 hp at the rear wheels on the dyno. 38,000/ 4.54 Mack rears, 177,900 miles.

The truck has been sold.

Thanks again. The dyno sheet for my engine shows 16.5 psi boost @ 2100 rpm, down to 15 psi at 1500 rpm.

Thanks for the information. Different injectors and pump setting from the endt673- and a different turbo?

I am looking at a dynamotor sheet which lists the engine as engine model # ET673-260 with a serial # of 4B7058. What is this engine? The sheet says 260 hp @ 2100 rpm. The dyno sheet is showing 188 horsepower at the rear wheels with 15 pound boost and exhaust temperature at 850 f.

There are multiple wiring diagrams in the Wiki section of this website.

2/8/2017- Tractor is sold.