Author Topic: Headlights not auto adjusting  (Read 2192 times)

0 Members and 1 Guest are viewing this topic.

Offline GrahamHay

  • S Class
  • *
  • Posts: 2
  • Gender: Male
  • I need to update my signature strip!!!
  • Body: Hatchback
  • Colour: Black Mica (16W) Metallic
  • Engine: 2.0L
  • Fuel: Petrol
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: Sport
  • Year: 2007
Headlights not auto adjusting
« on: July 04, 2017, 04:31:16 PM »
Hi - The headlights on my 2007 Sport are aiming very high (I'm getting flashed by other drivers).  When I switch on the ignition & lights they do not auto adjust (i.e no sound from the headlight motors and aim stays constantly and high).  The headlight auto adjust warning light does not come on (though has done in the past intermittently when driving in wet conditions).  I checked, disconnected and refitted the sensor on the back axle and all seems to be OK with that, so before I start pulling other things apart, is there any way to test whether its the control module behind the glove box or headlight motors themselves?  I doubt both headlight motors would fail at the same time to I'm leaning towards the control module.  The other posts on this subject all seem to state the headlight motors do work when turning on the lights but the aim is wrong due to a failed sensor on the axle but my case seems different in that the headlight motors do not even attempt to adjust when turning on the lights - I assume they are supposed to do that?.   MOT is due soon so need to get to the bottom of this without resorting to an extortionate dealer fix!   Thanks.

Offline Willpower

  • Administrator
  • Super Ultimate Class
  • *
  • Posts: 6542
  • Gender: Male
  • East Anglia Mountain Rescue Team
  • Body: Saloon
  • Colour: Winning Blue (27B) Metallic
  • Engine: 2.0L
  • Fuel: Petrol
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: Sport
  • Year: 2004
Re: Headlights not auto adjusting
« Reply #1 on: July 04, 2017, 09:31:33 PM »
Hello and welcome to the forums.
Yes the lights SHOULD auto adjust and go through the sequence on every ignition as long as the lights are switched on.  As you seem to have done some reading on this problem, then I would say that in my opinion the control module is faullty.
Look at life through the windscreen, not the rearview mirror.
2004 Winning Blue 2Ltr Sport Saloon.  Laser Blue Main beams.

Offline GrahamHay

  • S Class
  • *
  • Posts: 2
  • Gender: Male
  • I need to update my signature strip!!!
  • Body: Hatchback
  • Colour: Black Mica (16W) Metallic
  • Engine: 2.0L
  • Fuel: Petrol
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: Sport
  • Year: 2007
Re: Headlights not auto adjusting
« Reply #2 on: July 07, 2017, 05:06:34 PM »
Quick update - I swapped out the headlight levelling control module (the one behind the glovebox) with one I found cheap on ebay, and no change - headlights still don't move up/down when switching on the ignition with the lights switched on, and one is still aiming high, so looks like the fault is elsewhere.  I adjusted the headlight level manually in the end using the 10mm bolt on the back of the light cluster.  I also tried turning the white plastic wheel attached to the back of the headlight motor but that didn't seem to have any affect on the headlight aim which seems strange - I thought that's what it's there for?   

Maybe the problem is the motors but seems strange they should both not work.  The wiring to the motors has 3 wires - 1st wire recorded 11v permanently, middle wire 9v permanently, 3rd wire 0v (this is when the lights are switched on).  This seems a bit odd but maybe normal?.  I tried connecting a battery directly to the motor terminals in various combinations and nothing happens, though I wasn't sure which terminals to connect +'ve and -'ve to so may not be a conclusive test.   Does anyone know how to test if the motors are working, and what voltage should be a the 3 wires connected to it?

Offline moozmooz

  • Sports Class
  • ****
  • Posts: 364
  • Gender: Male
  • Body: Hatchback
  • Colour: Blue Reflex Mica (42B)
  • Engine: 2.0L
  • Fuel: Petrol
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: SE L Nav
  • Year: 2016
Re: Headlights not auto adjusting
« Reply #3 on: July 08, 2017, 12:34:43 AM »
This is something I have no experience of as I didn't have this on my old 3 and I'm not well enough at the moment to crawl under my new 3, so I'm possibly totally wrong.
I'm assuming that the sensor is a swinging arm wiping a variable resistor. If that's the case, you should be able to simulate high and low resistance by open circuiting and short circuiting the feed from the level sensor to the module. If that gets some sort of response, the chances are there's a problem with the sensor.

Going forward from there, it would be nice to be able to do continuity checks on the wiring, but without a wiring diagram, that's not going to be easy.
I've not seen a control module so again I'm shooting in the dark, but are you able to do any checks with a voltmeter/resistance meter to compare your original module and the replacement? There's always a possibility that your replacing a dud with another dud.

Are the voltage readings you've given the same for both motors?
You could try connecting your voltmeter with the lights off then check how the voltage changes when you switch on for each wire. If the system is working correctly, I would expect to see some variation in voltage as it tries to adjust the headlight level. Then get the heaviest person you have available to hop in the boot and repeat the test. Again, I would expect to see a difference between loaded and unloaded in one or more of the voltages if there's any output from the sensor and control module.
I'd hope that lot would give you a reasonable indication as to whether it's a sensor/control problem or motors.

If you don't already have it, you can access the workshop manual here http://www.mazda3forums.co.uk/workshopmanual/ . As with your current problem, it tends to never have what your looking for, but it might come in handy at some stage.
 
 
 

Mazda 3 Forums UK

Re: Headlights not auto adjusting
« Reply #3 on: July 08, 2017, 12:34:43 AM »