Auto Head Light Fault

[Guest gaztank]

i own a c5 est, when i start off at night the headlights point in the normal direction but as i pick up speed the headlights flicker and adjust themselves and point to the floor and i cannot see ahead, where is the leveling sensor located as i know the back end lowers as you speed up but the lights are over adjusting. any ideas

[mlkey]

i own a c5 est, when i start off at night the headlights point in the normal direction but as i pick up speed the headlights flicker and adjust themselves and point to the floor and i cannot see ahead, where is the leveling sensor located as i know the back end lowers as you speed up but the lights are over adjusting. any ideas

 

Don't know too much about these, but pretty certain the height sensors are used, and located on the front and rear anti roll bars. If your suspension is behaving correctly, it is unlikely to be these, although you may want to have a check and clean / lubricate the sensors. Am guessing there is a control unit somewhere which interprets these signals and adjusts the headlamps accordingly.

 

I would clean the height sensors and see if the problem persists as a starting point.

 

NOTE: Ensure the vehicle is supported by axle stands or a jack before touching these sensors.

[myglaren]

Have you the Xenon headlamps? They have independent leveling motors.

 

Standard headlamps don't as the ride is always level (in theory). It may well be your car is not riding level as it should.

 

I may be wrong on this but believe that C5s have optical height sensors, completely different to the Xantia/BX/CX/GS/DS types. May just need cleaning.

[Randombloke]

i know the back end lowers as you speed up but the lights are over adjusting. any ideas

 

Changes to ride height with speed only apply to H3+, I think. Haynes agrees. Usual caveat, ask the techs, barbsc1, kfk, iannez or techbod.

 

Look under the bonnet on the cover to the hydraulics, H3 or H3+ is written there.

 

Information to drive the Headlight motor ECU comes from the height correctors/sensors according to Haynes.

 

It also warning about the voltages on Xenon lamps.

 

If the car is not levelling properly, squirt the height corrector ball joints with WD40. If it is, and the lights are still going haywire, then you have a motor or ECU fault.

 

The headlight flicker is usual and is caused (AFAIK) by the electric motor that drives the hydraulic pump cutting in and out.

[Guest gaztank]

Changes to ride height with speed only apply to H3+, I think. Haynes agrees. Usual caveat, ask the techs, barbsc1, kfk, iannez or techbod.

 

Look under the bonnet on the cover to the hydraulics, H3 or H3+ is written there.

 

Information to drive the Headlight motor ECU comes from the height correctors/sensors according to Haynes.

 

It also warning about the voltages on Xenon lamps.

 

If the car is not levelling properly, squirt the height corrector ball joints with WD40. If it is, and the lights are still going haywire, then you have a motor or ECU fault.

 

The headlight flicker is usual and is caused (AFAIK) by the electric motor that drives the hydraulic pump cutting in and out.

[Guest gaztank]

thanks for the input, when the weather gets warmer i will have a look. and treat myself to the new haynes manual. i was hoping the sensors were in the engine area, as i was told by some body it may be in the overflow tank on the cooling system.