2015 TLX Fog Lights - Only on when headlights set to auto?
 

Hi -

It appears that the fog lights on my 2015 TLX will only turn on when the headlights are set to auto and it's dark enough for them to be triggered. They won't turn on when I manually set both the headlights and the fog lights to on (say, in heavy rain, but in the middle of the day). Therefore, there's no way of switching on the fog lights on when it's not dark enough for the automatic lighting to engage.

Here's what I've observed:

* Dark outside: headlights set to auto, fog lights set to on ---> headlights off & fog lights on
* Light outside: headlights set to auto, fog lights set to on ---> headlights off & fog lights off
* Light outside: headlights set to on, fog lights set to on ---> headlights on & fog lights off

I'd expect fog lights to be on in the third situation above.

This wasn't the way it was on my 2009 TSX. I could turn them on during the day if the headlights were switched to on.

I'm wondering if this is correct behavior or if the dealer did something wrong when installing the fog lights (I got them installed the week after I bought the car).

This behavior isn't mentioned in the manual. Page 168 just says:

"When the low beam headlights are on, turn the fog light switch on to use the fog lights."
and
"The fog lights go off when the headlights turn off, or when the daytime running lights are on."

Thoughts?

- Mark

Wild. I don't have fog lights personally. When in doubt, ask the dealer. :2cents:

You'll find the install instructions for the fog lights here:

https://acurazine.com/forums/fifth-g.../#post15084225

Page 13 has a table as to when the foglights will be on. Summarizing, they'll be on when the Headlights are set to "On" or "Auto" and they're on low beam while the fog light switch is set to "On."

Basically, if the headlights are set to "Auto" you'll most likely be in DRL mode (all 5 lights lit) as opposed to the low beams being on (3 lights lit). The fog lights will only illuminate in low beam mode.

I always keep my lights to Auto and my fog lights to on and they come on whenever I need them but I was curious so:

When I got home from work today it was sunny and I parked my car with the sensor directly in the sunlight.

I set the headlights to parking lights (the second setting from the bottom) and the fog lights to on and only the DRLs came on.

I set the headlights to on (the bottom setting) and the fog lights to off and only the headlights came on. I left the headlights on and turned the fog lights on and both came on.

I know there are sensitivity for AUTO, but I don't think they would matter when the settings are on so I'm not sure why your fog lights aren't coming on.

Your best bet would be to ask the dealer. The only thing I would say was that maybe you had the setting to parking lights instead of all the way down to ON.

Hope this helps.

Thanks for this. That table reflects the behavior I'm seeing so I guess it's expected! It seems odd that I can't turn on the fog lights during the day but I think the situations where that is needed are few & far between.

- Mark

Hmmm. I tested mine today and the fog lights DID come on during the day if I turned them and the headlights to ON.

Are your fog lights original or dealer installed?

Interesting..

Mine are dealer installed. I'm going to comment on it the next time I take the TLX in for service, regardless.

- Mark