#1-When changing tire sizes from stock 245's to new 265's the 265's will register 2.3 mph to slow. Is this difference recalibrated in the computer by the dealership or does it require a change of the spedo gear in the transmission like the older models (non-computer)?? My van is a 2004 E-350.
#2-Factory installed daytime running lights are programmed through the computer using the dim mode on the headlites. That being the case why dont the lights turn off when the key is in the ACC position. Meaning that you cant listen to the radio when you are working on the vehicle?? Is this an option that can be reprogrammed in the computer??

 

Tire size/axle ratio's are programmed into the PCM/VID block..

The DRL's are on a stand alone module that pulses the low beam voltage for a reduced output, and aren't PCM controlled.. Looking at the DRL circuits, it looks like you could re-route/remove the ACC/ON leg for power distribution at the module connector (ACC/ON function)change itto ON/RUN key postion power only and elliminate the ACC switch control byremoving the LB/PK (on with ACC/ON) and routing another key ON power source to the module as a splice leaving the DRL's intacted but operating in ON/RUN only.....