the other thing you can do is pull out the ash tray. you'll see a white "nub" sticking out slightly. If you reach under the dash you'll grab a connector that the nub belongs to. With a slight twist you can get the nub to release from the hole in the dash so you have access to the connector. The connector is the light for the ashtray. One wire is ground , the other is the dimmed 12V for the bulb. You can use a volt meter or a test light to find the hotside.
If you tap off of the headlight switch directly, you must do it with a fuse. It's not fused - yet. That wire from the head light switch dimmer heads over to the fuse block and becomes fused by fuse #5.
If you use fuse #5 with a fuse tap, turn on your headlights so the instrument panel lights are on. Pull the fuse (the instrument lights must go out if it's the correct fuse), using a voltmeter or test light test which side is hot, you want the fuse tap on the other side.
-Bob