I haven't really played around yet for a dimmer, but searching this forum for a rheostat is easy enough, and/or on google is probably where I found photos, etc.

The rheostat is just simply a device in your cluster area, at least on the car the google search showed. You might even be able to YouTube it as well, and watch a video. But the device is just some little electronic thing, and you clean it because it becomes pitted over time, and builds up an electronic resistance, causing some of your lights, etc., to malfunction.

Since I've already put my cluster back in, I'm not going to mess with mine. Getting the cluster out was a total TRIP!!!! Man, that was hard! I didn't bother undoing some of the things shown on the previous link I posted, since I was just trying to change one bulb. I replaced 3 since I was there, the 2 dash and the glow plug light. Not a job I want to re-do anytime soon, so I replaced what I could.

If you need more advice on getting your cluster out, to get to your rheostat, let me know via email, not private messaging, as I'm not on the forum a lot. I can sell you the tools I bought, they're German Mercedes tools. $28.00 includes shipping.