Mack Granite Engine Brake Not Working

I changed the relay and checked the switch but they both are ok.

Mack granite engine brake not working.

I do have a fuse panel on top of the dash and one at the kick panel by the drivers door but it does not have a label. I was talking to another driver today who drives a granite he says there is an oil pressure line that controls the engine brake and there is a small valve in that line that gets gummed up. The reason for high cutting out and only low working is that the engine brake is not getting the required oil pressure to function properly. Ca engine interface mp 11 19 na o ignition battery sw spare connection 47 cb o dpf regeneration system 20 nb junction posts 48 cc engine heater 21 nc additional ign.

I looked at the schematic it says the fuse for the comp. Federal and canada motor vehicle safety standards mvss 106 brake hoses and 121 air brake systems. Any change or addition to the system may cause the vehicle to no longer be in compliance with. When the ignition switch is turned on the engine brake solenoids are supplied a constant 12 volt direct current with current flow increasing whenever the engine brake is activated.

I noticed about 2 months ago it would not work all the time only once and a while. I have not checked the power. About a month ago it quit working entirely. The j tech engine brake is activated by the v mac system.

The truck is a 2004 mack vision daycab. I did find one with a loose connection for the sol. To properly diagnose electrical problems with the brake an ammeter may be required. As manufactured by mack trucks inc the air brake system on mack chassis both incomplete and complete comply with the applicable requirements of u s.

The multimeter model i use to troubleshoot listed on the amazon affiliate link listed right here. The model of this truck ctp713. Brake solenoid is fuse 2 in the engine compartment i have not found any fuses in the engine compartment. Battery switches 1 3 49 cd urea dosing system 22 ne additional ign.