Hid Headlamp Levelling

[kenny 2]

i own a 98 ls400 with hid headlamps pre air suspension,and have got a warning on the dash saying,headlamp levelling,can anyone tell me what can cause this fault.

[steve2006]

Hi,

Firstly welcome to LOC.

For the HID headlight leveling there is yet another ECU behind the dash called ( believe it or not) the headlight beam level control ECU.

The information for the ECU is provided by 2 sensors 1 behind each headlight called the Beam Level Control Accuators.

With these being in quite an exposed position ( damp heat etc) I would locate and check the wiring connections are ok 1st.

There are also ride height sensor inputs to the ECU but not sure if these are active in non air suspension models.

The only other alternative is the Lexus Stealer at Pride Park for a diagnostic check.

If you can read circuit diagrams and diagnose yourself let me know by PM and I will post you a copy of the wiring involved.

Good luck

[kenny 2]

Hi,

Firstly welcome to LOC.

For the HID headlight leveling there is yet another ECU behind the dash called ( believe it or not) the headlight beam level control ECU.

The information for the ECU is provided by 2 sensors 1 behind each headlight called the Beam Level Control Accuators.

With these being in quite an exposed position ( damp heat etc) I would locate and check the wiring connections are ok 1st.

There are also ride height sensor inputs to the ECU but not sure if these are active in non air suspension models.

The only other alternative is the Lexus Stealer at Pride Park for a diagnostic check.

If you can read circuit diagrams and diagnose yourself let me know by PM and I will post you a copy of the wiring involved.

Good luck

hi steve my car has got ride hieght sensors one one o.s.f and o.s.r ,when car is started and headlamps are put on they self test and work ok,then if warning light comes on the dash then there both plane spotting! dont know if that helps,ive bin told that the hieght sensors ***** up? hope to hear back....kenny2

[steve2006]

Hi,

Yes the ride height sensors do fail ( Lexus have in the past replaced under warranty with cars under 6 years old) and the signals from these are input into the headlight level ECU.

If you PM me your contact details I will copy the manual section so you can locate and check the condition of them before having to pay £££££'s at the dealer.

[Chris Skelton]

Wow! Something else to worry about as the dark winter days set in! (And I recall Citroen DS lights that went around corners! But that was all done by wires!

[GoldfingerLS]

There are two sensors for the headlamp leveling. one on the frotn suspension and one on the rear suspension, can't remember if they are on driver side or passanger side. Could be a lose connection on these suspension mounted sensors ?

Then apart from that as Steve says Beam Level Control Accuators located at the headlamps or the ECU. Could be a faulty control accuator.