Broken fog light or rear defroster switches? Fear no more, they're rebuildable!_Guide

[corrado33 10]

Ok, so I've recently been annoyed with the fog light switch and rear window defroster switch in my (new interior 93+) rado. It was very weird, the fog light switch WORKED, meaning it would switch the fog lights on and off, but the ring wouldn't light up to tell me that they were on. The rear defroster switch didn't... seem... to work, although my newly destroyed drivers side mirror would indicate otherwise (the rear defroster switch also controls the heated mirror(s?). If it is left on for too long, the mirror will go all brown and cloudy and ruined.) However, I had no idea if it worked because if it did, the outer ring ALSO did not light up when it was on.

 

Now, I've not tried to buy these new online, but I have done a cursory look by googling. Some (most) sites say that the switch is no longer available, which makes sense. Some sites say that they ARE available and you cay buy them for a few 10s of dollars/euros/whatever. I'm inclined to believe the former over the latter. Regardless, these switches aren't getting any more available, so in the future all we may have is the option to rebuild them.

 

First off, it's worth noting that the INTERNALS of these switches are IDENTICAL, save for one... tiny part. And that part is easy to replicate with a simple piece of metal if you lose it or want to switch from one side to the other. You can also flip it over, bend it a bit and switch sides if you'd like. The part that differs is the "see-saw." The one on the rear window defogger has 2 "bumps/contact points" and the one on the fog light only has 1 "bump/contact point." Why is this? Well, we'll get into my ideas why later when we get into the pictures. For the corrado though, the different design serves literally zero purpose because all 3 contacts connect to the same metal bar. Basically, what this means is that you can LITERALLY change one switch internal into the other switch internal with just a few minutes of work and a tiny bit of soldering if you want the lights to work. (And the soldering is all out in the open and easy to get to.) With that said, they do have different part numbers (at least mine do.)

 

So I decided to take them apart and fix them. And fix them I did. Here are some pictures. I'll make comments where necessary.

 

Also, considering that the file size limits here are... pitiful, I've uploaded them to an image hosting site, which means that eventually the internet will forget about them and they'll be unavailable, so I've also provided a link at the end of the article with all of the image files in a zip attached to my google drive. That should hopefully stand the test of time.

 

These are the two switches I'm talking about. Mine have part numbers of 535959621A (Rear Defroster Internals) and 535941535C (Fog Lights Internals.)

 

Top Image:

 

Side Image:

 

 

 

Now, these are pretty easy to take apart, but you have to remember that they're made of 25+ year old plastic. Just BE GENTLE. So here's how I took them apart.

 

You need two flat screwdrivers. One tiny screwdriver (like as small as you can find within reason) and one normal sized flat screwdriver that has these type of "serrations" if possible. (Just makes it easier.)

 

 

Now, use the tiny flat screwdriver to insert between the "shell" of the switch and the internal part of the switch, then gently place the larger screwdriver in it's place. The point of what we're doing here is to raise the outer shell "holes" above the plastic bits on the internals that catch.

 

 

Now flip it over and do it again. Once you've sufficiently "pried" (again, plastic, it's really not a prying motion.) the two parts apart, the back end should just pull out gently. There is literally nothing else holding the back end in, so there should be very, very little force needed.

 

 

Mine literally just popped out.

 

Here they are partially separated.

 

 

NOW BE FREAKING CAREFUL FOR THIS NEXT PART. DO NOT... AND I MEAN UNDER NO CIRCUMSTANCES TILT THE OUTER PART OF THE SWITCH WITH THE OPEN END DOWN. There are two LOOSE springs inside that will fall and you will never find them.

 

 

See them in there? Above and below the white "light switch" looking thing? Yeah, they're not held in at all. I HIGHLY recommend taking them out with a pair of tweezers and putting them on something magnetic, or in a jar or something.

 

 

These springs are one of two sets of easily loseable parts that cannot be replaced easily in this mechanism. Just don't lose them.

 

The other easily loseable parts are the spring steel pieces on the sides of the mechanism that are used to hold the switch into your dashboard.

 

 

These (one per side) slide out toward the open end of the outer shell. I also recommend removing these and placing them with the springs so you don't lose them.

 

Anyway, now that we've gotten the springs inside and the "springs" outside removed and safe, there is literally nothing else to do with the outer shell. Yes, it CAN be taken apart further, and if your little white "light switch" looking thing is broken, you will have to do that. But otherwise there is LITERALLY nothing else to do up there. So just put it aside.

 

So long as the inner and outer "plastics" are still lighting up appropriately (with a flashlight behind them), as shown, there is, again, zero reason to go up there.

 

 

If you must remove the delve deeper, then what you have to do is pry these two tiny little plastic pieces toward the middle of the switch body. So basically insert two tiny screwdrivers where the green lines are, and push the screwdrivers APART at the back end so that they wedge off of the body and push those little plastic pieces together toward the middle of the switch. While doing this, also pull the switch "button" off. It's not terribly hard, but the plastic there is EXTREMELY thin and prone to breaking. I personally used a tiny screwdriver (the yellow one in previous pictures) and a pair of tweezers to shove in there. Again, it took virtually zero force to pull the switch out once those plastic pieces were properly pried apart, so don't go ape on it.

 

 

 

Ok, now onto the business end of these switches.

 

 

See how in the following image the metal "see-saw" has two "nipples" on it? And to the right there is an additional unused nipple?

 

 

See how it compares to the fog light switch?

 

See how in the fog light switch picture the "single" nipple is used where as the "double nipples" are not?"

 

Now, here's where I'm going to speculate a bit. All three of the nipples are connected on the same piece of metal. You can see this metal front and center on the last pic. So, you may ask, why does one have 2 nipples where the other has 1? Well, if you look closely... below....

 

 

You'll see that this piece of metal has a "cutout" that goes 90% of the way through. This cutout would separate the "dual nipples." Meaning that if you wanted to, you could modify this switch to have additional functionality by cutting the rest of the way through that "cutout." You could have this one switch control two different things (with additional wiring in the harness of course.) Well... technically THREE different things if you migrated the other switches internals up to this one. Just... food for thought for anyone who needs additional switches in their car and wants to keep it stock looking. I won't get into the wiring of how to make it happen, and if you can't figure it out you probably shouldn't be messing with it in the first place. Just remember, the "see-saw" portion of the switch connects a metal contact underneath itself to the metal piece with the 3 nipples on it. The piece with the 3 nipples on it has THREE populated connections in the wiring harness, and they all are obviously connected with 0 Ohms relative to each other (save for the one connected to the incandescent lamp which has a bit of resistance due to the parallel resistance of the lamp itself.) Anyway, enough speculation. Back to rebuilding these things.

 

I've had to end the post here because it's too long. I'll continue in the first reply.

Edited December 11, 2019 by corrado33

[corrado33 10]

Ok so now we're left with the internals of the switch perfectly intact. If you move the plastic piece back and forth (rotation wise)you should see open circuit and a short (respectively) on these two pins.

 

 

EDIT: I LIED!! The internals of the switches AREN'T identical. One has two "keys" for the wire plug to "key" into, and other other only has one. Those keys don't do anything but make sure you plug the plug in correctly, so they could be shaved off if you really wanted to switch them. Look up top of the picture above. The right one has 2 "slots" and the left one only has 1. (Fog lights is 2 slots, defogger is 1 slot)

 

(Again, the switches are identical and the pins that run across are all shorted together (because they're all part of that bar with the nipples on it.) So basically, if you rotate the black plastic piece one way, these two pins will be at open circuit (megaohms), and if you rotate the black plastic piece the other way, the'll be shorted (0-1 ohms). You can actually use this test before even taking apart the switch to see if it's working correctly.

 

So now we can take off the "black plastic piece". It's not held in by anything other than the plastic "clips" on each side of it. So all you have to do is CAREFULLY pull it out. It doesn't take a lot of force... but it does take a bit. I just used my fingers, no tools required. AgaIn, old plastic, brittle, try to avoid doing this too much.

 

After the black plastic piece is removed, you can then remove the metal "see-saw" piece. It's literally not held in by anything but a bit of friction. You may be able to "shake" it out, but I had to put some tweezers in there and lift it out.

 

 

Now we can see all of the pieces for the "internals" of this switch. All 3 pieces.

 

 

Now, you can see on the "black plastic piece" that it has a spring loaded end. This end should move in and out FREELY, so put a drop of oil in there but make sure to wipe all the excess off so it doesn't short anything in the switch. Now, you'll notice that the end of my "spring loaded bit" is... well... ugly. That's because it's worn to crap. Here's a comparison with one that's worn and one that's not as worn.

 

 

So what this means is that there is no need for metal contact between the spring loaded bit and the metal "see-saw." In fact, if you can avoid it, you'll likely avoid some wear.... which is a good thing. I debated putting some thin teflon on top of the metal "see-saw" or on the end of the spring loaded piece... but my switch still worked so I didn't bother.

 

Anyway, at this point I LIGHTLY cleaned the metal contacts on the metal "see-saw" (the two nipples, and the one hidden contact underneath, as well as the nipples and fulcrum for the see-saw on the switch part itself.) I had to use a bit of sandpaper as mine were corroded. Don't sand it too much of course. Just the lightest of cleanings. Wipe it all off with some plastic safe solvent (rubbing alcohol / isopropyl alcohol / pure vodka) Don't use brake cleaner, acetone, or nail polish remover as it'll likely melt the plastic.

 

Now is a good time to check the bulbs on the switch. The green one is an LED, which means it's likely NOT broken as they nearly NEVER break. And even if it is, there are a freaking trillion of them in the world you can use to replace it with. (You need a smaller than normal LED. I don't have a pair of calipers handy, but LEDS typically come in 3mm and 5mm variants, and this is certainly a 3mm one. (And it's green.)

 

Anyway, now to test the LED and incandescent bulb.

 

Look at the side of the switch with the lights and wires.

 

 

EDIT: Flip pin 1 and 3 if yours is the fog light switch and looks like a mirror image to this one. Basically just look where the bulbs are. The metal bar furthest from the white incandescent bulb is pin 3, always, regardless of switch.

• Connect 12V between contacts 2 and 3 to test the white incandescent light. It's bright. One of mine was broken.
  
• Connect 12V between contacts 1 and 2 to test the green LED. Now, LEDs are polarized so if it doesn't work, try switching the polarity. Yes, this LED has either been wired to handle 12V or it's a special 12V LED because it didn't break at all when I put 12V across it with zero current protection. Although I don't suggest doing it for long. However, if you are afraid to blow it up, you can also test the LED with the "diode test mode" or "continuity mode" on your multimeter. Pin 2 is ground (black), Pin 1 is positive (red). It should light up (dimly) if you do this. Both of my LEDs worked perfectly. (EDIT: I measured it in the car, the LED voltage is regulated from 12V to 0V by the internal light dimmer inside the car.)
  

 

Anyway, if your incandescent bulb doesn't work, you can take a look closer with a little magnifying glass or a jewelers loop. It's just like a normal light bulb, you SHOULD see a little coiled wire strung between the two "posts". I tried to take a picture through a little magnifying glass.

 

 

EDIT: The closest matching bulb I can find online is an EIKO 8640. Although that's discontinued... so I'm not sure what the replacement would be. (I lied, you can still find them (found mine on bulbtown.), I'll let you know how it matches with the original brightness of the original bulb.)

 

Yeah, horrible picture, I know. It IS possible to see it by naked eye, but BARELY, and only IF you have a crap ton of light. And unless you have something to compare it to you likely won't be able to see if the coiled wire is there or not. So get your a magnifying glass. Again though, just like a normal incandescent bulb for your house. If the coiled wire is there, the bulb SHOULD work, if it's not strung between the posts, that means it has burnt out and you'll need to replace it.

 

At this point, if your lights work, and your switch works, you can put it back together and be relatively assured that it'll work. You do want to make sure that the "black plastic piece" does move back and forth with relatively little effort. I just worked mine back and forth with my fingers a few dozen times and it was all good.

 

 

Anyway, that's pretty much it. I have a HUNCH that the incandescent bulbs in these switches are identical to the ones that are on the back of your instrument cluster, it's just that the ones on the cluster are mounted in an nice little plastic thing. But if you removed it and soldered it in place of the one on the switch, I bet it'd work. I'm going to try that... as soon as I find my spare bulbs for the instrument cluster.

 

All in all, these switches are EXTREMELY simple. There's nothing special about them. They're just physical switches. In my opinion, not worth the money to pay for new ones or for ones people are overcharging for on ebay. Also extremely easy to mod say if you're doing an LED internal lighting mod.

 

As promised, here's a link to the pictures' album, provided postimage hasn't deleted them. They're on my account... so... technically... they should stick around for a while.

 

https://postimg.cc/gallery/31eqs30um/

 

And here's the link to the zip file from my google drive.

 

https://drive.google.com/open?id=1AQi62mMdBTtFW2jkDwBFIkXF-uXPEZgD

 

EDIT: After messing with these switches some more (and purchasing 2 other ones to play around with), I've learned a few things.

1. Some of the switches come with that little piece of connecting copper between the two sides of the switch drilled out. One that I bought had a tiny little hole there.
   
2. The incandescent bulbs inside the switches CAN be replaced with the "DW07" bulb at "bulbtown.com" I replaced mine it it works perfectly well. (Obviously you need to do a bit of soldering, but it's simple.) I wouldn't go for the lower wattage DW21 bulbs cause the DW07 seems to be the correct brightness. I purchased the 8640 bulbs from bulbtown as well, which seem like they'd also work, but I didn't try because the DW07 worked just fine. Bulbtown ALSO has green tinted bulbs... which are used somewhere in the Rado... I forget where.
   

 

I now have about 40 bulbs that could be used to replace these.... since they were so cheap I just bought... I think 25 of the 8640s, and 6 of each of the DW07 and DW21, and then... for some godforsaken reason... 16 of the green ones. I really have absolutely no idea why I bought that many of the green ones... but I did. I think I may have mistyped when ordering. The individual bulbs are less than 1 USD each, and you CAN order individual bulbs... I just figured "hey, I may as well order a crap ton."

Edited January 14, 2020 by corrado33

[corrado33 10]

Reserved 2

[fla 9]

Thanks for sharing.

Have you got any ideas for a wide dispersion led for the heated seats switch?

[Philly-R6 0]

Excellent work!

 

I always wanted to put a push button to drive the central locking from the inside in that blank next to the demister switch. I'm inspired now....

[corrado33 10]

Thanks for sharing.

Have you got any ideas for a wide dispersion led for the heated seats switch?

 

I did BRIEFLY look at my heated seat switch. The lamp is NOT LED, unfortunately, it's another one of those tiny incandescents. It actually looks to be identical to the white ones in the switches above, but it's tinted green. Honestly even non-wide dispersion LEDs are bound to be brighter than those bulbs, so I'd stick one in there just to see what happens if yours is broken.

[corrado33 10]

Excellent work!

 

I always wanted to put a push button to drive the central locking from the inside in that blank next to the demister switch. I'm inspired now....

 

Do it!!! That'd be awesome. I'd love to see it.

[corrado33 10]

Inspired by Philly-R6's comment above, I've tried to think of a few things one could put inside the "empty" switch bays on each switch.

 

Some Ideas;

 

• Central Locking
  
• Cruise control speed up/cruise control speed down
  
• I'm unsure how the ecode light "motors" work, but those buttons could control the motors if need be.
  
• Ignition shut off switch (relayed of course.)
  
• Seat belt release for people who don't know about the rado moving seatbelts and will inevitably hit their head...
  
• Oil Slick
  
• Rockets
  
• Passenger ejection seat
  
• Camouflage
  

Edited December 11, 2019 by corrado33

[Keyo 47]

A direct line to the vehicle roadside assistance or the credit company. ha

[corrado33 10]

A direct line to the vehicle roadside assistance or the credit company. ha

 

I don't know if my Rado is special or not, but it has never once left me stranded.... anywhere. Sure, I've had issues occasionally, like my window fuse blowing in the middle of a 106 degree DC summer... then I had to park and roll the windows up (with the key), and I subsequently had to drive home 2 hours in 106 degree heat with no windows and no AC. (That was a hot day.)

 

But really, my corrado has been super... super reliable. (Knocks on wood.)