A multimeter from Radio Shack should do the job fine. Around $40 - it will be a long term investment for all sorts of projects with your car and house, so it's not a sinngle-use expense.

Shut down car.

Disconnect NEGATIVE battery cable.

Set multimeter to measure current (aka amps).

Connect one end of meter to negative cable lead - one end to negative battery lead.

Check for current draw. I'm guessing that you'll be noticeably over 0.10 amps.

Open your fuse box and start pulling the fuses, one by one - checking any change in the current as measured by the meter. (Replace each fuse if nothing changes with the current). If you find a fuse that, when pulled, causes a noticeable drop in current, then you've found your suspect circuit.

TO THE OTHER BOARD MEMBERS - have i missed anything here? It's been a while since I did this.

Good Luck,
Troy
1995 E420