2002 F250 7.3 Liter

Can someone help me? I've recently replaced the 7.3 in my 2002 F250. Now the batteries are being drawn down after the engine is turned of for 6-8 hours. The alternator tested good. Between my two 7.3's I have a combined milage of over 800,000, and have never experienced this problem. Any suggestions would be greatly appreciated.

Thanks Guys
FISH

Welcome to the forum!

You're going to have to help us help you by doing some troubleshooting to at least determine the circuit that is providing the load on the battery. Probably the easiest way to do this is either with a DC clamp on current probe (not real common for the average DIYer) or a test light. I'll assume you have a test light and will go this route. Disconnect the positive battery cable and install the test light in series with the positive cable. You'll see a rather bright light in the test light that should get dim within a 15 or so seconds. Since you suspect a drain, the test light may not dim in your situation, but wait a couple of minutes just in case. Assuming after a couple of minutes the light is still glowing rather brightly, start to remove fuses one at a time while monitoring the light. If you have a mapping showing which size fuse goes where, you might want to consider leaving the fuses out as you pull them rather than pulling and reinstalling before pulling the next fuse. The reason is you might reset circuit timers if you reinstall them which could give you false indications on the test light. When you pull a fuse that causes the test light to go out or at least get really dim, that circuit is likely the circuit that has the drain in it and you can narrow your search to items on that circuit.

-Rod

Thanks for the response. You are the second person to suggest this approach. I will let you know the results if you are interested. Again thanks.

Fish