Help Needed - Headlight Switch Assembly Replacement

I've never worked on this problem before, but I recommend going to a wrecking yard and pulling the replacement part to get some practice on how to do it before you work on your own car...

Judging from the pictures though, maybe one of those round stickers that obviously don't stick very well got inside there and caused this problem?

 

To get the steering wheel off the generation 3 remove the access panels where your light and wiper stalk stick through You take a piece of plastic or your finger and those things pull out and you pull them off the end of the stalk and set them on the ground then inside you will see a straight fat piece of metal that looks like it's part of a paperclip It's a u-shaped clip that goes from the top of the hole that you just took the cover off of down to the bottom You grab it with a pair of pliers and pull it out and down or lift it up It's a real pain in the butt instead of two screws like in the generation 2 they replaced the screws with this bent metal clip You may need to look at some videos they're probably some online I'm not the only person that's taking the steering wheel off the generation 3 It's pretty routine actually It's a sucky system to mount the wheel but oh well You want to have everything aims straight ahead when you do this after you get the pad off you can follow the instructions for the generation too you'll need to remove the orange and black plugs off the back of the airbag lifting up the yellow clips popping off the wires undoing the wires at 12:00 off of the clock spring then undoing the 19 mm nut wiggle the wheel and it's off and you set it on the ground on top of the airbag and now you're staring at the clock spring and attached to the clock spring or your light switch and turn signal I'm assuming you're replacing this whole assembly It's clamped on to the tube look behind.

 

Yeah you can pull them off like that if you want You changing just the headlight switch or the whole assembly You might want to go to a junkyard and look at a car and somewhat a disassembled state The plastics I've had off the generation 3 they just pull off I guess I thought there was a screw on the bottom piece of the plastic to hold it in place on the assembly If not you can feel it if it's not there then they're just pull apart clips they don't need you to do anything you just rip pull them up and pull the bottom one down usually I don't do that till the steering wheels out of my way because I'm working on other stuff that requires the steering wheel to be off If I'm taking the master combination switch assembly off I'm sliding it over the steering wheel shaft but if you're just replacing the stalk that has lights or wipers on it I think you can take that off without sliding anything over the steering wheel shaft. And if that's the case well there you go But that seems to me like that's going to take a whole lot longer time and a bunch more screws personally usually I replace the master combination switch because in my car I'm adding the fog light ring and all of that to turn on and off fog lights which on generation 3 you may or may not have I can't remember. So I'm usually taking the steering wheel off If you don't have to do that then you won't have to take the horn button off either I don't think If you can finagle around to get your switch assembly off whichever it is wiper or lights I guess you could work that way seems to me be like working around my backside to get to the front but yeah okay this is a 15 18 minute job here at my house generally speaking on the cars we own here I just ripped the steering wheel off of the generation 3 to put it on my generation 2 last week out of a persona sitting here in the yard The clips you have pictures of you grab those with your needle nose pliers and you pull out and you lift up you'll get it if you try it a couple of times try pulling on the pad as you're lifting up the thing that looks like a giant paper clip when you get it lifted up and pulled back a little bit one edge of the pad will start to come undone now you got to reach over to the other side and do the same thing on it when you get it just right the paddle come flying off and dropping your lap almost it'll be hanging by the wiring If you feel the need you'll undo the 12 volt to undo the yellow clips on the orange and black connections to the airbag I don't my car is just turned off and the remote's not near it click click drop the wires in the steering area hole that you just created removing the pad then I undo the other two cord steering wheel buttons and cruise control but if you can get away without taking that off by all means have at it it'll just take you an hour and a half to do the work versus about 20 minutes with the stuff out of the way but that's a personal call

 

Strange choice.
Why for example not an integration relay?
Or why not wiring from the Main Body ECU?

Do you have a car with LED?

 

So you have a regular generation 3 with h8 and h11 bulbs in place halogens or their equivalents or something? If so this is a car that had wiring harness problems from the factory I think for some reason there's an updated part maybe have a look I think there's a wiring harness that may be in your future That's just for the headlights

 

Four wires go from the Headlight Dimmer Switch Assembly to the Main Body ECU.

Conventionally, by shorting these contacts to ground, the low beam, high beam and side lights are switched on.

Therefore, you can use the input contacts in the Main Body ECU and check the inclusion of external lighting options by shorting them to ground.

 

The output control signal comes from the Main Body ECU via the contact group of the board to the green wire, which goes to the integration relay. The relay in turn sends power via two wires to the right and left side of the low beam via the purple wires. Outputs HLPR (1) and HLPL (2).

 

Certainly it's possible. I would leave it connected and test with a meter on the green wire connecting the body ECU's HRLY output (2C pin 32) to the relay's HL4 input (1G pin 9).

If that signal changes state as expected when you turn the switch on and off, that would suggest everything is ok as far as the ECU and the relay isn't responding to the signal. If, on the other hand, you don't see that signal change, something is funky between the switch and the ECU.

... and of course if the signal changes at the ECU end of that wire and not at the relay end, something's happened to the wire.

 

You can put the black lead on any unpainted body metal. Sometimes there will be a clip attachment for your lead, so you can clip it onto a nice unpainted bolt head or something and then have your hand free.

It's a negative-grounded system. Ground is not 'switched'. The 12 volt purple wires running to the bulbs are what is switched (by the relay).

Now, the wires running from your stalk switch to the ECU, the switch connects those to ground when turned on. So it "pulls down" the respective ECU inputs when turned on.

The green wire between the ECU and the relay, I'm not totally sure whether that works by going to +12 for on, or pulling to ground for on. That's why I cleverly said "if the signal changes state" when you turn the switch on and off, so I could sound like I knew what I was talking about without actually committing to which way it should change. Anyway, with your meter on it, whichever way it is when your switch is off, you should see it go the other way when your switch is on.