[AT] tractor hauler a pain to install headlights.

[Steve W.]

Phil Auten wrote:
> 
> 
> I haven't checked my Ford Fusion, but then I just turn the lights on and 
> never use the "auto" position on the switch. My F-150 does not have that 
> option.
> 
> Phil in TX
> 

I think there is a bit of confusion in regards to the auto light 
function and the DRLs.

Many DRL systems do not turn on all of the lights. They only activate 
the headlamps at reduced output. There are some that turn on all the 
lights but they are not the most common.

The automatic lights usually have a sensor on the dash that detects the 
exterior light level and turns on all of the lights once the light is 
below a set level, just as if a human turned the switch.

I have seen those get fooled though, usually in bad weather where the 
light gets reflected back to the sensor by for or heavy rain or snow. 
The backscatter is enough that it exceeds the threshold and the system 
switches back to the DRLs.

-- 
Steve W.