TheDurk
Elite Member
I have a '99 manual so I know the ADD circuit pretty well. You could wire a manual over-ride to the ADD VSV's that would keep the ADD from engaging when activated. Use a DPDT and have one side open the circuit to the engage VSV and the other side supply 12V+ to the disengage VSV. Simple, and done right on the firewall. You would need to take four wires back into the cab to the switch--three if you source the 12V+ inside the cab.
Or use a relay on the firewall to do the same thing and then just one wire into the cab and an SPST switch.
Or use a relay on the firewall to do the same thing and then just one wire into the cab and an SPST switch.
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