Hi, I recently purchased an 89 STD, and none of the lights on the dash come up when i turn my lights on (turn signal indicators, battery, cel, ect all work fine)
After having an issue with my main relay and taking it apart to re solder broken connections, i figured i would attempt to do the same with the dimmer switch if possible (just assuming that the dimmer switch is the issue)
I have not attempted the repair, although i am posting pictures and a small guide to take apart the dimmer switch to see if yours is bad. (im going to have a friend of mine do it, he is much better at soldering than i am)

This is a very easy task, I took a ton of pictures and tried to describe everything in detail so a 10 year old could probably take this thing apart

Tools:
A pretty small Flathead screwdriver
14mm wrench, or adjustable wrench

Step 1: Take out the dimmer switch, I was able to just reach my hand up under my dashboard and pop it out by pressing it towards myself, took very little force and then i just unclipped the wires connecting to it once i got it out




Step 2: Take off the back cover, there are 4 very small clips holding it in, i recommend starting on the side with the plug (since there are smaller clips inside that hold it on that you cannot get to)

Obviously be careful so you dont break anything, it might take some back and forth since the plug side will want to stay intact, i wouldn't completely pop out either side at one time







Step 3: Getting the **** off, Its very simple, it is just friction fitted on to splines that have a flat keeper side (i assume this is a potentiometer but i dont know enough about electronics to say for sure)

All i did was stick the screwdriver behind the **** and pry a little on each side until i was able to just pull it off by hand




Step 4: Take off the nut and washer, I used an adjustable wrench, but you can also use a 14mm. its not tight at all just spin it lose and you'll be able to slide out the PCB from the plastic shell.



Step 5: Inspect the solder joints on the back side (green side) of the PCB. Look for any cracks or burns.

They are kind of hard to spot, after looking at mine there are a few that i think are possibly cracked. The next 2 pictures are what the board will look like when you take it out of the case.





This is a photo of my own dimmer switch and the connections that i think are definitely cracked



Okay thank you for reading this very in depth tear down for a very simple process, I have never tried to make any forum post or write up that describes how to take something apart like this and I hope it helps at least one person.

I am aware that there are 2 different styles of dimmer switches in 88-91 civics, mine came out of a 89 STD.
For now i am going to put 88-91 in the title until someone corrects me because i cannot find which dimmer switch goes in which car.

 

Excellent

 

Perfect post. And yes, that is exactly a cracked solder joint. Same thing happens in main relays. Just need to reflow the solder to fix.

 

I do not believe you. This is a fantastic write-up, and I will definitely be referring to it before too long. Many thanks!

 

That's the 88-89 style dash dimmer, the 90-91 is a smaller wheel type- rheostat to the left of the gauge cluster and a remote circuit board under the dash similar in size to the 88-89, black plastic box with cooling holes.