I have a 1999 F150 XLT and want to switch the fog lights on seperatly with a different switch. Is there anyone that knows which wires to short at the headlight switch connector ?

 

I tried to use this link (https://www.ford-trucks.com/articles/may2002/drls.php) on my '01 Lariat but it was not good for me as I guess the light switch has been changed. Also the wire colors were not the same. I did manage to find all I needed to do the following while into the dash. These instructions got me into the general areas. I now have my factory fog lights on as DRL's that come on with the key, off at the start position, and off with the key, not on in the acc position. I also use the fog light postion on the main headlight switch to operate a relay that powers up the 100 watt KC's on the grill gaurd. They can be turned on in either high or low beam now also. I do wish I could figure out how to modify the switch to be able to pull out the fog position any time instead of just with the lights on.

I found power from behind the heater control as the article above mentioned, only a different color. I pulled my switch out and found it did not come apart as suggested in the article. What I did was just to get a meter and look for the wires I needed. Sorry I did not copy the color info for others to use. If you get in a bind, let me know and I can pull mine apart again to get the info you need.

 

When the fog lights are turned on the headlight switch grounds the yellow wire which goes from the switch to the fog light relay. It looks like you could just add in your switch, have one side of it to ground and splice the other to the yellow wire. The fog light indicator light on the main switch should even light up still and the main switch would still turn the fog lights on too if you wanted

 

I have studied the mod that has been posted with the function chart and the logic chart. I dont have an electrical diagram and would like to know if you pull the wire that goe's to pin 5 and apply 12 v+, would this turn on relay 27. According to my owners manual this is the fog lamp relay. I have 1999 F150 XLT and it has the older style switch and circuit board assly. There is no auto lamp.

 

The manual shows that pin 5 on the headlight switch is for the dash lights.
Like I said before...try grounding the yellow wire.

 

seems lik eyou guys know whats gong on so i have a ? thats been pissing me off.Ihave a 2002 f-150 SC it didnt come with fog lights.IPUT A AFTER market airdam that came with lights.now i had them hooked up to a targa that came with it but the relay went out .i wanna hok them up to the wires that are there (factory installed for the lights)but iam not getting anything.On the drv side there are two plugs one i get juice from but the lights dont go out and on the pass side there is just one plug....plz.help thanks