Hello, My 1996 P38 has been sitting at repair shop for a couple of months due to drainage on battery. I would charge battery and the Rover would start. 3 more times turning over the engine and the battery would be dead. I changed the alternator with new one. The same problem. I took vehicle to the repair shop and they had Becm tested and there is no problem. Becm tested fine. My next option is to replace fuse box with new one. The repair shop is stumped. I need help. Thank you.

 

At this point, a clamp on DC amp meter makes diagnosis a bit easier, it clamps around the cable and reads the amps, without "inserting" the meter in series with the circuit. So I can put the clamp on my D1, see the starter draw almost 300 amps when turning over, then go back to charging at a few amps when engine is running. Juts read amps coming from alternator and see where they go. It is important to have a good battery that does not have a dead cell. And every connection (battey posts, fuse box cables, fuse links, ground connections for battery and starter) be clean and tight.

A meter like this

Without a meter, the old school way was to use a tail light bulb in series with the circuit. High drain made bulb glow bright, pull fuses to make that go away. You could also disconnect large wire from alternator and crank truck, running on battery reserve only, while metering for 12 volts and unplugging fuses to isolate. So you are not trying to keep up with the drain by having alternator on.

There have been reports of strange drains from a variety of things, like air suspension valves that jam on after vehicle turned off, sub woofer amps in back doors shorted to some other cable and draining the batt, wire haness skinned or melted rubbing against metal (shake the harness), etc.

You may have a simple electrical problem and a skilled mechanic that is not used to electrical issues. There are specialty shops that rebuild alternators and starters, and usually can troubleshoot this sort of thing.

 

Hello Buzz,
Thank you for your response. Now, I'm wondering when I had my mechanic about a year ago convert air- suspension to coils could be the culprit. I know the pump and the valve block were removed. However, I periodically hear a motor running.

Anyway, I'm going to have the Rover towed to a more experienced shop that has the right equipment before I throw anymore $$$ with a new fuse box. I will post results when I receive a new diagnosis. A lot of good information in your response to my dilemma. Especially, the links. Many Thanks.

 

You said the magic words. The air parts run after truck is turned off to keep leveling it. Unplug connector c151 (pump) and c152 (valves). These are the grounds to those units, and will keep them from stealing power in a vain attempt to keep vehicle level after ignition off. The compressor draws the most, but valve solenoids can drain a battery as well. See attached pix from RAVE service manual.