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Discussion Starter #1
I finally got round to opening up and repairing the square dash switches. I had a few dodgy switches, ranging from blown bulbs to unreliable contacts. I bought some used switches and took them apart to learn how they were put together.

It does take some fiddly work and there are some tiny parts and tabs, but worth the effort, IMO.

Here's how you disassemble one of them without breaking them. The switch has 4 assemblies, 2 x 2 held together with tabs.




To open it up, first pry the tabs at the bottom of the switch assembly. I used spectacles screwdrivers to pry them apart.




This is what it looks like inside. This one had 2 switch contacts which were bent when someone force-pressed the switch. There are 2 loose parts when you open it up - the spring, and the lever which gives it the rachet movement. You can see the resistor that gives the bulb low illumination when the switch is not depressed.

I cleaned up the contacts with some contract spray and sandpaper. I also straightened and repositioned electrical contacts that were misaligned.




To get to the bulb, you need to pry open the other assembly - the one that mates the black push-button with the white switch assembly inside. To do this, you'll need to locate the white tabs through the little windows on the side of the switch. You'll also need another person to help you. While you press the white tabs down (one side will do), have another person use a long-nose plier to grab the white slider guide with one hand, and at the same time pull the black button with the other hand. It should come off with a bit of tugging.




You can get the blown bulb at this point with some delicate soldering. When putting things back together, here's a picture of what it looks like with the rachet lever in place. Make sure you slide the "fingers" on the black part between the electrical contacts and the white slider guide.

 

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Great write-up ...

I had to open up one myself to repair not iluminating emergency lights switch - it was so fiddly and hard to get that front piece apart ... finaly I managed but still with some breaking the plastic, then glueing it back together ...

Mod should take this up as the sticky ...
 

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KurBads said:
I had to open up one myself to repair not iluminating emergency lights switch - it was so fiddly and hard to get that front piece apart ... finaly I managed but still with some breaking the plastic, then glueing it back together ...
...I just replaced all the switches with ones that did light up...

Mod should take this up as the sticky ...
Indeed.
 

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Discussion Starter #7
No, there isn't a separate spring for the rachet mechanism.

The rachet mechanism is rather simple and don't really go wrong. Your problem might be traced to the rachet lever that's disengaged either from the round pivot above, or the small pin at the end of the lever thats lifted out from the white plastic "canals" below.
 

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Discussion Starter #10
Reposting with Pictures

I finally got round to opening up and repairing the square dash switches. I had a few dodgy switches, ranging from blown bulbs to unreliable contacts. I bought some used switches and took them apart to learn how they were put together.

It does take some fiddly work and there are some tiny parts and tabs, but worth the effort, IMO.

Here's how you disassemble one of them without breaking them. The switch has 4 assemblies, 2 x 2 held together with tabs.




To open it up, first pry the tabs at the bottom of the switch assembly. I used spectacles screwdrivers to pry them apart.



This is what it looks like inside. This one had 2 switch contacts which were bent when someone force-pressed the switch. There are 2 loose parts when you open it up - the spring, and the lever which gives it the rachet movement. You can see the resistor that gives the bulb low illumination when the switch is not depressed.

I cleaned up the contacts with some contract spray and sandpaper. I also straightened and repositioned electrical contacts that were misaligned.




To get to the bulb, you need to pry open the other assembly - the one that mates the black push-button with the white switch assembly inside. To do this, you'll need to locate the white tabs through the little windows on the side of the switch. You'll also need another person to help you. While you press the white tabs down (one side will do), have another person use a long-nose plier to grab the white slider guide with one hand, and at the same time pull the black button with the other hand. It should come off with a bit of tugging.




You can get the blown bulb at this point with some delicate soldering. When putting things back together, here's a picture of what it looks like with the rachet lever in place. Make sure you slide the "fingers" on the black part between the electrical contacts and the white slider guide.

 

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Discussion Starter #13
Phase 2 - replacing the bulbs with LEDs. Picked blue ones for the AC snowflake switch. Never seen it this bright before...



The LED are those meant for auto use (12v) and can be dimmed. But I haven't figured out the right resistor to replace the existing one for when the switch is not depressed - it remains just as bright now. But it's 10x brighter, consumes a fraction of the power, does not "yellow" the interior through heat, and will last a lifetime....
 

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Dash lights work sometimes

I thought I was going to have to tear apart the dash to replace the dimmer switch but then suddenly the lights worked....now they are off again :-(

Since I have a junkyard switch and tons of bulbs I'll probably dive in there and see if that is the problem, any other ideas on what could cause this problem?

Sean
89 turbo convertible
 

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I thought I was going to have to tear apart the dash to replace the dimmer switch but then suddenly the lights worked....now they are off again :-(

Since I have a junkyard switch and tons of bulbs I'll probably dive in there and see if that is the problem, any other ideas on what could cause this problem?

Sean
89 turbo convertible
Could be the contact of the bulb holders on the PCB track (a common problem). Give the holders a wiggle and see if the lights come on. Also the wiper contact in the dimmer pot can get dirty. Wiggle the dimmer backwards and forwards a bit. This often cures the problem. Diving in there should be avoided unless you have patience, care and time.
 
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