328 Battery Drawdown

My 1989 328 GTS, with a brand new battery, will not start after sitting in the garage overnight. I placed an ammeter in series with the negative terminal and find I have a parasitic draw of 3.25 amps with the key off. My next step was to remove and replace each of the fuses, one at a time, and found the draw unaffected at 3.25 amps. The next step was to remove and replace each of the relays, with the same result. I next removed the smaller two cables (which I believe are routed to the fuse and relay board) of the three cables bolted to the positive battery clamp, and still saw a draw of 3.25 amps. This indicates to me that the problem lies somewhere in the larger cable (~1/2” diameter) of the three cables on the positive battery terminal. All of the lights, instruments, and accessories are working properly. At this point, I am at a loss. Has anyone experienced something similar?

 

Thank you Steve. I was coming to the same conclusion that I have an alternator problem. I checked the red "battery" light on the dash, and it is not "on" with the key "on" and engine not running. Like you, I noticed in the wiring diagram that there is a connector on the positive cable, so I will look for it tomorrow. I'll update you when I am able to disconnect the positive cable.

 

Update: While laying on my back under the car, I was unable to disconnect any of the cables leading to the starter or alternator in attempt to isolate the current draw. As a result, I scheduled an appointment to take the car into my mechanic tomorrow morning to address the 3.25 amp parasitic draw. However, before doing so, we decided to do a Ferrari event today, which included a 165 mile drive. At the end of the drive, I rechecked the battery draw and find it now to be only 20 milliamps. I have no idea what's going on. Could the draw be associated with the ABS system? I'm still taking the car in tomorrow to discuss with the mechanic. I will continue to update this thread until the bitter end.

 

I just checked the warning light and it is working correctly. I did a cold start, ran the car for 30 seconds, shut it off, and rechecked the draw. It is still at 20 milliamps. When I turned the key off, the ABS warning light stayed on for about 15 seconds, and I noticed a buzzing sound from somewhere around the battery/brake reservoir area. I recall this happens frequently lately.

 

Final update: Steve, you were correct. My mechanic removed the alternator and did a complete overhaul, including new bearings. The bench test showed the alternator output was insufficient to maintain the battery, even with all accessories off. After the rebuild, even the power windows operate faster. The parasitic draw is now zero with the clock and radio fuses pulled (20 milliamps with the clock and radio fuses in). In response to Formula Junior, my car is completely stock, except for the Kenwood radio, which has a small draw even when off. By the way, my car has 37,000 miles, and the R&I and alternator rebuild was approximately $1000, money well spent. Thanks to everyone for their support and thoughtful posts.