Door Courtesy Light Flickering

[Steven]

For many people here who've done LED upgrades to their interior, you'll probably find the door courtesy lights develop a random flickering effect after doing the swap to LEDs.

The reason for this is the poor connection the door switches have to earth when open.

The following is a method to fix this problem, however it's a bit involved and you can very easily bugger your switch if you're not careful so follow at your own risk.

First of all you will need to remove the switch, which requires the removal of a T30 Torx screw. Once unscrewed simply pull out and unplug it. If you don't have enough slack you might need to unplug from inside the car. I found I had plenty of slack on the back seats, but for the fronts I needed to partially pry off the lower B Pillar trim panel and unplug from behind.

Once free, remove the black weather proof cover. Now to disassemble the switch you can do it the proper way, or my way. If you know the proper way then that's fine. My way involved grabbing the steel mounting plate with my left hand, and pulling the back of the switch off with a pair of pliers. For me the switch came apart very easily and didn't cause it any permanent damage.

NOTE - I just tried this method again and it resulted in the switch being damaged. I would suggest not to unclip it this way, but try to unhook the clips that hold the back half on. It's a bit more time consuming but it's far safer.

Once apart you have the following parts.

The first part of the fix involves reshaping one side of the metal flange that sits inside the "pin". The side you want to reshape is that which makes contact with the tab on the steel mounting plate part of the switch.

Try to match the above shape as best you can. Essentially you are just making the contact area larger, but also longer as well. With a pair of needle nose pliers this is fairly straight forward.

The second part of the fix requires you to make the long flange on the rear half of the switch a tad more inward, but still shaped so it flows back on itself.

So if the flange is like this ------^

You want to shape it a bit more aggressively like this _______/`\ if you get what I mean

Now that's sorted you can reassembled the switch. Test with a multimeter to ensure you have a circuit with the pin is fully extended, and no circuit when the pin is pushed fully in.

The next part is optional, but I found it gave the best results as it removed the free play from the plastic switch housing and made it far more solid. Take a lighter or soldering iron to the seam between the 2 halves of the switch and melt them together. You don't need to melt it very much at all to make it very strong. Removing this extra play makes the switch contact stay that much more stable once reinstalled in the car.

Reinstall is the reverse of removal. Hopefully you should now have a flick free door courtesy light.

NOTE

Please check to ensure the light does in turn off when you close the door fully. If it doesn't, then you'll need to drill a very small hole in the tip of the pin and insert a small screw. This will allow the door to push the switch in that tiny bit extra to ensure it turns off. I only had this problem when doing my back doors using a different method to the above.

[Steven]

Also best to clean the mounting screw when reinstalling. Toyota in all their wisdom decided to paint/coat the screw, which can affect the quality of earth you will get. A quick polish with a grinder/file will see if earthing that much better.

[DJKOR]

Just don't make em as solid as they used to eh. Good work on figuring this one out.

I'll add this into the FAQ when I get a chance.

[450HP/tonne]

I have 3 new switches I can donate to the cause ... should a stuff-up occur.

[FMAN]

Do you know why this fixes the flickering? I thought the interior lights were driven by the Main Body ECU which gives a delay when the door is closed. This should isolated the lights from any minor door switch problem or are the LED lights wired directly to the door switches ?

[DJKOR]

Do you know why this fixes the flickering? I thought the interior lights were driven by the Main Body ECU which gives a delay when the door is closed. This should isolated the lights from any minor door switch problem or are the LED lights wired directly to the door switches ?

The lights we are referring to here are the individual door courtesy lights. The door switches provide ground for the Body ECU connection (so your dash can tell you which door is open) as well as grounding the light as well.

For reference:

[FMAN]

Thanks, that make more sense.

The flickering is probably caused by the switching of the pull up resistors in the body module when switch resistance has increased.

Switches need a certain amount of current to clean themselves (depending on design/contact materials).The LED’s are not supplying this current so I suspect even after this modification the problem with return. I am not sure if the increased contact surface area will be better or worse as you have less current per square mm but more area to contact.

To prevent the problem you need to increase the current. You could put a resistor in parallel to the LED but this would generate a lot of heat (similar to the bulb). Depending on how long the flickering takes to appear, you could refit the bulbs until the switch cleans itself.

Are there any other Toyotas that use a similar switch with no door light and only a connection to the ECU? This might have different contact material.

Sorry to cast doubt on your solution and not provide a helpful alternative

[Steven]

Thanks, that make more sense.

The flickering is probably caused by the switching of the pull up resistors in the body module when switch resistance has increased.

Switches need a certain amount of current to clean themselves (depending on design/contact materials).The LED’s are not supplying this current so I suspect even after this modification the problem with return. I am not sure if the increased contact surface area will be better or worse as you have less current per square mm but more area to contact.

To prevent the problem you need to increase the current. You could put a resistor in parallel to the LED but this would generate a lot of heat (similar to the bulb). Depending on how long the flickering takes to appear, you could refit the bulbs until the switch cleans itself.

Are there any other Toyotas that use a similar switch with no door light and only a connection to the ECU? This might have different contact material.

Sorry to cast doubt on your solution and not provide a helpful alternative

I'm afraid you're simply over thinking it. The flickering was caused by a poor connection in the switch itself, due to the freeplay the switch has internally which causes the contacts to easily become sub-par. The contacts themselves upon inspection were perfectly clean, just very poorly aligned. This mod is about increasing the average surface area regardless of the free play within the switch, so it maintains a good contact. Further by "welding' the plastic on the exterior housing it does a bit towards removing a bit of the free play.

The flickering most people notice occurs the instant you switch to LEDs. If you're theory was correct, then the flickering would take time to appear once changing to LEDs. In reality the "flickering" is always present, just less observable when using bulbs due to their lower sensitivity to voltage fluctuations.

[Steven]

updated the instructions re: disassembling the switch.

[DJKOR]

Thanks Steven.

For a note, Steve did this for my driver's side door switch. Prior to modifying the switch, my door light would flicker ever few seconds or so and lightly tapping the door switch would also make it do it. After modifying the switch however, the flicker is completely gone. Even jiggling the door switch did not make it flicker.

[ryan184]

Sorta on the same topic....

Would it be illegal to have lighting underneath the car that is connected to the drivers door switch...

To have the effect that they would come on only when the drivers door is opened. (just to be different)

I have read through what I believe is the Government documents online and say that you can have under car lighting any colour as long as the car is stationary.. anyone know if this is correct?