Electrical stuff is my weak point so hopefully yall can help. My headlights dim (not drastic but noticeable) when I push the brake pedal, or push a window button, or a mirror switch or wipers pretty much any of the controls. Like I said Im weak in the electrical department so fire away with any ideas.

 

Dimming lights are not really abnormal so to speak, both my cars will do this say when the fan kicks in( my 850 doesn't really do it much actually). Just the battery having more of a load on it when some components kick on. My 97 Camry has always dimmed when I press 2 or more windows at one time.

So getting back on topic, 850's don't have capacitors because they don't draw that much power( look up a capacitor if you don't know, because I know what it is but not how to explain it). If you are concerned it wouldn't hurt to check on the condition of your recharge system. Take a volt meter and check the battery under load.

If you really want me to think of some fault, then just your alternator might not be that good anymore due to the high age of these cars and might be time for a new one. To me, I wouldn't be concerned about your dimming lights if you find your recharge system(alternator) is recharging your car well. That's just my 2 cents!!

Here is a video if you want to just investigate more about checking your electrical system. He has other videos about other components as well, and this stuff applies to all cars;

 

You can also try cleaning up your cable connections to see if that helps.