Custom fog light install wiring

[Boyd]

I'm working on a harness for a set of fog lights on a '21 Mach 1. I'm using a GT headlight switch which has the foglight function included. I'm not paying hundreds of $'s for a harness that only partly does what I want.

Can anyone confirm my suspicion that the headlight switch simply controls grounds to the BCM? I've done a lot of searching and this seems to be the fact. I do not plan to use the BCM at all for this project, just the headlight switch.

I'm also looking for confirmation that headlight switch gray wire pin 14 as being the one to cut into (going into the headlight switch) to get that foglight switched ground for a relay.

Please dont ask about lights, mounting, etc. I have some thoughts on that, but no real work yet. I'll post up when I have something complete.

Thanks...

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[traxiii]

Looking forward to what you come up with!

 

[MACHtobers Very Own]

So am i )= I want fogs badly. cause ya know... theres CUTOUTS THERE!

 

[Boyd]

Sort of answered my own question... The GT headlight switch with the fog light function sends 3.0vdc to the BCM indicated switch on/off. So that cant be used to operate a traditional relay.

Leads to my next question... I'll find a ForScan thread to ask this one.

 

[Boyd]

My intention: Investigate if factory-like fog light wiring is possible in our Mach 1's.

1. Installed a GT fog light / headlight switch in my Mach 1. That switch outputs 3v at pin 14 gray to connector C2280B pin 20 gray at the BCM. This wire is factory installed and working.

2. The BCM does not need programming to enable or disable the fog lights.

3. The BCM outputs 12v to the fog lights in BCM connector C2280G pin 5 Ye/Or Right and pin 12 Bro Left. It appears these wires do not exist in the Mach 1 wiring harness. Very difficult to tell because the BCM connectors use 90 degree stress relief. But looking from the open side of the connecter, it appears there's no pins, so no wiring from BCM to park lights for fog light operation.

4. It would be very difficult to add wires to the BCM connector. Pins are available, but requires special crimping tools and disassembly of the BCM connector. Broken plastic pieces are a real possibility, so adding wiring to the BCM is not a real winner of an idea.

My result is that we do need to use an external relay / switch / wire harness to operate any type of fog light on the Mach 1. Using the GT fog light / head light switch is not possible because it only supplies a very small signal voltage to the BCM... nothing capable of triggering a relay.

I know some may think this is ridiculous, I'm just trying to do this the best, right way. I know there are harnesses out there for just this purpose and the easy thing to do is just slap it in. But I'm a retired aircraft mechanic... I don't just slap anything in, especially without knowing why.

I'll have more to post as this goes along. Follow or not, maybe it'll help someone some day.

Picture is connector C2280G at the BCM.

 

[Racer57]

Have you considered this ? I can change them to whatever color I want. 2021+ Mustang Mach1 Grill Halos | eBay

 

[Rael]

I'd be happy if I could glue in yellow or amber glass lenses without electronics.

 

[traxiii]

My intention: Investigate if factory-like fog light wiring is possible in our Mach 1's.

1. Installed a GT fog light / headlight switch in my Mach 1. That switch outputs 3v at pin 14 gray to connector C2280B pin 20 gray at the BCM. This wire is factory installed and working.

2. The BCM does not need programming to enable or disable the fog lights.

3. The BCM outputs 12v to the fog lights in BCM connector C2280G pin 5 Ye/Or Right and pin 12 Bro Left. It appears these wires do not exist in the Mach 1 wiring harness. Very difficult to tell because the BCM connectors use 90 degree stress relief. But looking from the open side of the connecter, it appears there's no pins, so no wiring from BCM to park lights for fog light operation.

4. It would be very difficult to add wires to the BCM connector. Pins are available, but requires special crimping tools and disassembly of the BCM connector. Broken plastic pieces are a real possibility, so adding wiring to the BCM is not a real winner of an idea.

My result is that we do need to use an external relay / switch / wire harness to operate any type of fog light on the Mach 1. Using the GT fog light / head light switch is not possible because it only supplies a very small signal voltage to the BCM... nothing capable of triggering a relay.

I know some may think this is ridiculous, I'm just trying to do this the best, right way. I know there are harnesses out there for just this purpose and the easy thing to do is just slap it in. But I'm a retired aircraft mechanic... I don't just slap anything in, especially without knowing why.

I'll have more to post as this goes along. Follow or not, maybe it'll help someone some day.

Picture is connector C2280G at the BCM.

There are relays that use 3vdc to control 10a 12vdc
https://www.amazon.com/Channel-Opto...1_3?keywords=3.3v+relay&qid=1704775504&sr=8-3

 

[Boyd]

There are relays that use 3vdc to control 10a 12vdc
https://www.amazon.com/Channel-Opto...1_3?keywords=3.3v+relay&qid=1704775504&sr=8-3

HAHA! I talked to my brother about this and he came up with the exact same thing! I have those on order, be here wednesday. I'll be testing the GT foglight switch controlling this relay to power 2 led fog lights. That will be really nice being able to use a factory switch.

Thanks!!

 

[Boyd]

Have you considered this ? I can change them to whatever color I want. 2021+ Mustang Mach1 Grill Halos | eBay

I've considered it. Its not a bad look and it makes a good use of the horseshoe shape. I really want to be able to fill and use this empty horseshoe space. I might like to do some halos around the fog lights. To me, there's just that empty space that screams Ford went cheap without at least giving us the option of filling it in.

I havent posted up about selecting and mounting lights yet... I have at least 2 ideas that need to be worked through. Still working thru the wiring ideas I have.

Thanks for posting!

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