Rear fog washes out camera at night.Electrical question about reverse & fog light mod
 

I installed the OEM rear fog light with dual filament functionality. But now it totally screws up the factory rear camera contrast at night. Like the bright red is overexposed and makes everything else dim and hard to see.

So this is my question as I sit here at work before I get into it later. I'd like for it to turn off with reverse light, I don't want a switch on it, I want it automatic. So do both wires going to the reverse lights get ground when off? If so, thinking I can splice the ground fog wire to the positive reverse wire. And when I hit reverse it'll turn to positive giving the fog double positive therefore shutting it off.

That's really the only thing I need to know, are both wires going to the reverse light grounded when not being used?

I got it. Worked exactly like I said. Cut the existing ground to rear fog and used the hot wire from the reverse light. Because it's a ground when not used. And two hot wires to a bulb doesn't hurt it, it just doesn't light up. Now it shuts off completely when reverse is engaged.

I used a similar setup on my BMW side markers. Stock, they only turned on with blinker, off full time. So I cut the ground to it and spliced it into the front turn a HIGH filament wire. So now not only did it stay on full time but it flashed alternatively with the front turn. Tried this on Z but LEDs are a different animal. Didn't work.

did your dual filament bulb was a regular one or LED? do you have it wired up as another brake light i suppose?

I just have a dual filament bulb I had it wired same like a taillight, parking and brake. But this mod turns it completely off while reversing. I thought the added light would be better, but it was the opposite.

Oh I see, the low light was not an issue then, only when you press the brakes? BTW is your car auto or manual? I'm asking this since it is something I want to do on my z as well

for a second i thought you had ir night vision camera.

Wait there's pictures??

Even the low light affected it, but the brake light just made the camera adjust and dim the display down too much. I have a 6 spd.

Ok found a problem. This method bleeds power thru the bulb back into the circuit and turns brake lights on. Will all be fixed with a relay tomorrow.

Thanks! guess I have to look into it since it also wanted my fog light to be a fourth brake light

A "high-current" diode will do the trick. Should be cheaper and easier to install than a relay. And more reliable.

I'm going to radio shack today, can you give me a part #?

According to my back-of-an-envelope calculations you need somewhere around 5 Watts. I'd go with this one from RS. 5W should give you plenty of headroom. It may get hot, so mount away from meltable parts.

Edit: They carry quite a few diodes rated at >= 5W and >=20V. As long as it meets those specs, you'll be OK. Get one that will install easily.

Got it thanks! Put the diode between the brake light and rear fog. Simple.