I had a problem with my Suburban draining the battery. New fresh battery with a fresh, full charge measuring 12.6 volts. The alternator has been tested and is good. With all lights, etc. off. Doors closed, hood shut, so no clear drain of the battery. Approximately 24 hours later, the battery was at ~10 volts. I removed the positive battery cable and connected my DVM inline set to amps to measure the "drain" amperage. This measured ~5 amps which is way too much and is definitely the problem. I removed each fuse and relay one at a time while monitoring the DVM readout. When I removed the A/C relay and fuse, the amps dropped to .75 amps. I believe this was the reason why my battery keeps dying. I put a full charge on the battery currently. The battery measures 12.9 volts. I will see what the reading is in the morning....