I have a 1999 Toyota 4Runner and I converted my headlights and fog lights to LED. When I installed the fog lights they worked perfectly fine when I had the stock headlights in but once I installed the led headlights the fog lights wouldn’t turn on. When I switch the fog lights on the high beams turn on. I plugged in one LED and one stock bulb and the fog lights turned in perfectly fine, but once both are plugged in the head lights only work.. anyone have any ideas on why??

 

What LED lights are you using?

Do you have a link?

Are they directional (meaning you can only wire it up one way for the light to work)?

LEDs by themselves can only be wired in one way, but many manufacturers have started using small circuitry in the bulb housing to make them work wired two ways.

 

I just came across some threads on the web that were kinda confusing but since your dealing with the issue specifically search 4 runner fog light mod, some of the threads I came across were saying the fog lights were turning on the high beams etc after going LED, like I said the info is kinda all over the place but it might make more sense if you scroll through the results.