Question regarding the front headlight level sensor
 

I know I posted to a thread in the DIY section which I stumbled across and replied to before I realized that someone hijacked that thread and that convo really didn't belong in diy anymore... so I'm reposting it here, where I think it is more appropriate.

I have a broken front headlight level sensor rod. The bracket that's attached to the lower control arm is bent out, the rod was broken in half, and the upper bracket was sheared off. I have no idea when this happened because I haven't noticed anything strange about the headlights and the MIL has never lit up. I discovered it when I was inspecting the front brake pads and the broken piece was draped over the control arm.

I learned from the DIY thread that you could manually set the headlight level as long as the sensors themselves are functioning properly. I'm wondering if the previous owner had manually set the levels, because shouldn't this broken rod cause the MIL to light up sooner or later? I live in an area with lots of hills, bumpy roads, and steep driveways. Assuming that the sensors are working, then if the levels are manually set, could I avoid having to replace this rod and bracket? That's my real question.
Thanks.

I don't think the level adjusts on the fly but only when you turn the key on. Also I thought the sensor is actually on the back suspension not the front?
Maybe you are looking at the swaybar ends.
Post a photo so we can see what you are talking about.

Hi Jason, there is a sensor on both the front and rear suspension. This one is definitely from the front. I made a mistake earlier, the rod wasn't broken in half, it was only broken at the head where it attaches to the bracket on the front left lower control arm.

And also, if the headlights don't adjust on the fly, then what the heck is the purpose of the sensor(s)? I mean, you might be right, I'd just be baffled as to why you would want an unnecessary moving part?

You may find that the spindle on the sensor has corroded in it's bush and jammed. This causes the bracket to fatigue and snap.


In operation the system waits until you are driving at a constant speed for 3 seconds and takes the reading from the sensors, which it uses to adjust the headlight level accordingly. It does this once per drive cycle. It can be fooled by wiring a pair of resistors across the three terminals on each sensor, thus convincing the control system that the car is perfectly level. You would then adjust the vertical aim of the lights to specification. Of course doing so will mean you would dazzle oncoming traffic as soon as you load the boot (/trunk), so a potentiometer can be used in place of one pair of resistors to adjust the level reported to the control unit manually.


It would be preferable to source a good used sensor and bracket and simply replace it. Alternatively I believe rockauto.com sell new pattern part sensors