Originally Posted by mbushnell
I've looked at the wiring diagram for my Ranger, & it seemed as though it was the Smart Junction Box that determined whether or not the truck had DRL's. Is this true? Is as simple as unpluging the Smart Junction Box & plugging in a new Smart Junction Box that has DRL's enabled, or is there more work involved?
The DRLs are definitely controlled by the SJB. I don't know if Ford builds a unique SJB for Canada or not. I suspect not though.
Many modules are configurable for different features. For example, I know for a fact that the Central Security Module is the same part number in the 2003 Sport Trac and the 2003 Ranger even though each has different set of features turned on. The feature set is flashed into the module at the end of the assembly line and can be changed using a dealer tool.
Another configurable module is the one that adjusts its output to the speedometer to correct for tire diameter and, in some cases, for the axle ratio. The conversion is done in a 'black box' like the PCM, GEM or ABS module, it is set at end of line and it is adjustable by the dealer within the limits allowed by the manufacturer's calibration.
I have no proof but I suspect that the DRL function of the SJB may be present in the 2004+ U.S. spec Rangers. If so, then a dealer tool should be able to turn it on unless Ford has disallowed that adjustment.
If it came to that, swapping to a different SJB just to get DRLs would be cost prohibitive. I don't know the price but it is sure to be many hundreds of dollars. The SJB replaces several body modules and a fuse panel.
There are aftermarket kits available to convert to DRLs. I'm not familiar with them but some appear to simply be a way to turn the night lamps on with the ignition. The same thing could be done with a couple of relays similar to the way the factory Autolamps mirror works. Either way, it has to be far cheaper than installing a replacement SJB.