I eventually want to put auxilary fog lamps on the front of my truck and would like them to turn on with the factory fog lamps. Has anybody done this? Can you splice into the factory dash switch? I would also like to use the aux. lamps supplied switch as an override, so I could still just use the factory lights alone.

Non-electrician

 

The above diagram shows how to add your lamps. The "foglamp switch" in the diagram would be your aux lamp switch you where talking about.
Where the diagram says "Tap this wire into the low beam power circuit", you instead could hook this to the wire coming out of your factory foglamp switch. That way you turn the foglamps on, the aux lamps would come on too, unless you had them cut off with the other switch.

 

You need to have a relay to control your auxiliary lights. Normally, these come with the lights. The main power goes from a (fused) battery wire through the relay and to the lights. The control power can go from your factory fog switch, then through the auxiliary light switch and to the control relay's coil. Then if your factory fogs are on and the auxilary switch is also on, the auxiliary lights will go on.

Do not tap into your factory wiring without using a relay! They are not overdesigned and cannot handle any significant additional load.

In some areas it is illegal to have more than four lights on. Please use 'em responsibly.

 

franklin2 and MrBSS,

Thanks for the replies!! This info. will help me immensely. franklin2 thanks for going the extra mile and providing a diagram! I have posted a few threads lately with very little response and your post gave me a boost. MrBss, good point about the 4 light law, thats why I wanted to use the aux. switch as an override to only use it in severe weather/circumstances. Thanks again.

Merry Christmas,
Mike