FORScan and GEM Module Programming

[RussB08F250]

In the GEM I changed the fog light option from Not Equipped to Equipped with the hope that it would enable the SJB to trigger the fog lamp relay already built in to work with the replacement headlight switch I installed that has the fog lamp option. According to AI, the VIOLET/ORANGE wire already in my headlight wiring harness goes to the SJB and will trigger it to close the loop and send power to the fog lights. The GREY/VIOLET that would normally carry the current to the fog lights is not installed so I would need to add a wire to feed the aftermarket fog lights. When I turned on the fog lamps and used a volt meter to check which connector cavity the new wire would need to be connected to I got nothing. This tells me the SJB is either not being triggered by the headlight switch in fog mode or just changing fog lamps from Not Equipped to Equipped did not enable the SJB as I hoped. I could find no other fog lamp lighting options in any of the modules, so I am at a loss.

That said, I noticed that there are a lot more lines of code in the GEM AS-BUILT file than the GEM Module. Is there more programming I need to do in order to get the SJB to enable OEM fog lamp use? I have the aftermarket fog lamps installed with a switch on my dashboard and they work just fine. I would just prefer to have them work OEM instead. Any thoughts or suggestions would be appreciated. Thank you.

[ifrythings]

Helps to know what your working on.

[tractmec]

In the GEM I changed the fog light option from Not Equipped to Equipped with the hope that it would enable the SJB to trigger the fog lamp relay already built in to work with the replacement headlight switch I installed that has the fog lamp option. According to AI, the VIOLET/ORANGE wire already in my headlight wiring harness goes to the SJB and will trigger it to close the loop and send power to the fog lights. The GREY/VIOLET that would normally carry the current to the fog lights is not installed so I would need to add a wire to feed the aftermarket fog lights. When I turned on the fog lamps and used a volt meter to check which connector cavity the new wire would need to be connected to I got nothing. This tells me the SJB is either not being triggered by the headlight switch in fog mode or just changing fog lamps from Not Equipped to Equipped did not enable the SJB as I hoped. I could find no other fog lamp lighting options in any of the modules, so I am at a loss.

That said, I noticed that there are a lot more lines of code in the GEM AS-BUILT file than the GEM Module. Is there more programming I need to do in order to get the SJB to enable OEM fog lamp use? I have the aftermarket fog lamps installed with a switch on my dashboard and they work just fine. I would just prefer to have them work OEM instead. Any thoughts or suggestions would be appreciated. Thank you.

Echoing Ifry, yes it would have helped it you had related the vehicle you are working on! However if you are working on your signature vehicle(F250) as according to the Fog light Wire colour(Grey/Violet) then that is the switched 12 volt+ to the fog light assemblies from the relay!

That circuit is fed 12Volts+ from fuse F21 in the SJB! That fuse also provides 12 Volts to the Fog light relay coil so make sure that fuse F21 is present and Good(May have been empty on vehicles without factory Fogs)!

The switch you have installed should have a brown wire connected to Pin 6(Fog light On)! This pin is a grounding pin for the micro processor which controls the Fog light relay and probably "Auto" lights if the vehicle has that option(Reads signals from the Sun load sensor on the dash and turns the lights on in ambient low sun light if the switch is set to "Auto")!
The micro processor provides the ground for the Fog light relay coil and is triggered by the light switch grounding pin 6(Brown Wire) to the light switch pin 1(Black Wire to ground)!

This circuit can be checked if you have a PID in the SJB/Gem(Under the Oscilloscope icon and should be there now that you have enabled Fogs in the configuration) for the Fog lamp switch!
That PID should be able to show if the Fog lamp switch is grounding pin 6(PID shows on with switch pulled out and off with the switch pushed in)!
If not something is wrong in the switch(no continuity between pin 6 and pin 1 with the switch on or no connection on the brown wire to pin 49 on Connector 2280B at the SJB(Brown wire may even be missing on vehicles without factory Fogs)!
That brown wire should also be showing a small voltage(1 to 5 volts to ground approx) with the fog switch off and zero volts with the switch on! If it shows 0 volts in both positions and the wire is present, then no SJB reference voltage(VREF) is coming to the switch for some reason(Careful with this as micro processors are fragile use a digital meter if you have one)!

Not sure but if there was a configuration option for enabling Fogs in the SJB then that should have set the Processor to look for a ground(Switch on) on that brown wire to energise the relay coil ground connection, close the relay to send 12Volts+ power to the fogs on the Grey/Violet wire!

See this link if looking for a service manual and wiring diagram: https://charm.li/

Just some thoughts from an old mechanic!