99 suburban 5.7 4x4 Two weeks ago my battery started going dead after the vehicle sat for a few days. I'm not sure how old the battery is but it's been in the truck since I have owned it. I took it out and got it checked at advanced and they came to a conclusion of its not dead but its not all that good either. After that I started thinking about electrical drains and with the help of a neighbor I think we determined that there is a drain. We used a volt meter in line with the battery and it showed a drain. When I went to rehook up the positive wire to the batt, I noticed a fast clicking noise under the dash. This is with the key out of the ignition. I determined the noise to be coming from a grey metal box of some sort close to the emergency brake and in a real pain of a spot to get to. It has two sets of wires going into it one up high and one around the middle. Also this box is bolted in. Any idea what this is and if a noise under the dash is normal when hooking battery off and no key in ignition? Thanks in advance - - - Updated - - - Thanks for the tips guys. Just kidding! I may have got the battery drain figured out and it looks like it was as simple as cleaning the positive leads from battery. They were not real dirty but I buffed them out any ways with a wire brush after reading a couple of other posts and things seem to be working better no doubt. That still does not answer the question of whats clicking under the dash when no key is in and you get the battery hooked up. I would like to know if that is normal. Have a great Sunday folks!