Thanks for everyone's threads and suggestions for installing fog lights in our F-150s.

I want to install OEM fog lights and use an OEM headlight switch w/fog lights.

Can anyone tell me how to connect an aftermarket wiring harness to an OEM headlight switch w/fog lights?

Background:
I have a 1999 XLT V-6. It didn't come with factory fog lights and I've searched hard for the factory wiring harnesses for the fog lights in the engine compartment and near the headlight switch, but can't find either. I'm assuming I don't have either.

I've done the following so far:

1) Installed an OEM valance with fog light openings

2) Installed OEM fog lights

3) Purchased a Hella custom wiring harness with fuse, relay and pigtails for the OEM fog lights. I feel comfortable installing the harness, but not sure how to connect the wires to the OEM headlight switch w/fog lights.

4) Purchased a 99 OEM headlight switch w/fog lights

The back of both switches (my original one and the one w/fog lights) look the same except for the opening for a thin connector on the left (looking at the back of the switch). This opening was bare on my original switch but has 4 metal tabs that I believe are for the fog lights?

Does anyone know which wires from my Hella harness should be connected to which tabs?

Hope all this make sense! Thanks in advance for any help.

 

Jate to waste anyones time.

Think I've found the answers to my questions...after a thorough search. Believe it was Sccully who provided it in the past. Hopefully the following is it (if someone thinks it's not...appreciate some feedback :-))
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As long as the switch is really from a 1999 truck, this is what the factor setup would look like

Using the diagram in post #3 above, you would wire it similar to the ford diagram.

From the main headlamp switch connector:
1. White w/ black stripe wire to the terminal #85 on the relay.
2. Yellow wire to terminal #86
3. Check that black wire is to ground.

With this setup and the DIY relay kit show above, your factory fog lamp switch now operates the added relay.

If the switch is from a 2000 to 2003 MY, then the wiring is a bit different.

Do you know for 100% sure that the switch is from a '99 MY truck ?

 

When I did mine (same as you did basically) I used Fairlaners "how to install lights behind grill" tutorial and it worked for me. his thread is here https://www.f150online.com/forums/19...ind-grill.html

 

The plugs are different (among other things) between the two switches. If your new switch will plug into the wires in your truck, it's the right one.

Are you sure you don't have the plug for the fog lights in the cab of your truck (small gray plug on the right in the pic below). My '99 XL has wiring for fogs in the cab, but nowhere else.

 

Fairlaner...first of all thanks for all the great posts on this forum. Very informative.

I've looked again, and don't see the gray plug. I've got the 2 plugs to the left.

The switch I bought fits perfectly...so I got that right! It has the opening for the gray plug in your picture. In one of your other posts think you showed a diagram of this plug (C244?) that showed most of the functions being for the autolamp (which the new switch I bought does have). The 4th opening, 188 (W/BK) is for "Fog Lamps ON Indicator".

My Hella harness (Part # 87199) has 3 wires going to their provided switch...a purple wire to the positive (+) terminal of their switch, a black wire to the ground (-) terminal and a yellow wire to the remaining terminal of their switch which will illuminate the switch they provided.

I know I'm getting ahead of myself, but from the various posts I've read on the forum, I'm thinking I have to do this:

1) Connect the Hella purple wire to 275 (Y)[Fog Lamp Switch] in the middle plug of your picture (this spot is currently empty on the plug)

2) Connect the Hella black wire to 57 (BK)[Ground] of the same plug (I'd have to splice into this as there's already a wire there)

3) Connect the Hella yellow wire to the 188 (W/BK)[Fog Lamps ON Indicator] location where the gray plug would have been...this will illuminate the "fog light" part of the stock plug?

Am I making sense of this?

I think I'm good with the other parts of the installation...just to confirm the connections of the Hella switch wires to the stock headlight switch.

Thanks!

 

I only ran two wires into the cab to the switch ... one to the wht/blk wire (the far right pin of the four pins in the small slot on your switch), the other to the yellow wire on the larger black plug. I don't think that your second connection listed above is correct, but I think your first and third are. I'm sorry I can't be more help. I'm real weak on anything electrical, and I remember when installing the lights not understanding why they worked, but satisfied that they did work. If you still need the help, this weekend I could take a quick look at my truck and describe how I wired the lights.

 

Fairlaner,
Thanks so much for your help. I'll try the install this weekend and let you know...hopefully good news.