toad electrical problem

Last year after buying our 2004 Damon Challenger, we bought a 2012 Equinox for a flat tow.  That year we towed the car for about 7500 miles on two separate trips.  We had absolutely no issues with the car connected or disconnected from the MH.

A couple of weeks ago after a 7 month rest, we hooked up the Equinox to the MH as before and drove 300 miles to a CG.  Upon arrival the car battery was completely dead.  A friendly neighbor jumped the battery and we had no more trouble during the ten days there.  However, when we arrived home the battery was dead again.  I charged up the battery and drove it for almost a week before the battery again went dead.

After charging the battery, I removed the negative battery cable and noticed a significant spark.  I found that 3-4 amps were steadily coming off the battery.  After a few minutes the meter would back down to almost a zero reading (I assume from the battery manager).  Removing the meter for a couple of minutes and retesting, the escaping amps would again be about 3-4 amps - until the battery manager would begin to kick in reduce the drain. 

After researching several auto forums, I learned how to search for shorted circuits by removing one fuse at a time.  However, this procedure did not work for me.

I carried it to my local mechanic shop who kept it for several days until giving up.  Tonight, upon picking up the car, the battery was dead and I again had to jump start it.

I can't help but believe something happened to the car after it was towed on our last trip as it had never giving us trouble during the past two years.  I can't figure out why it continues to drain after it has been disconnected from the MH.

Any advice is appreciated.  John

Your car is a 2012... Delco batteries don't last for ever ! It is probably gone !
Did the mechanic make a charge test ?
If not, get him to do so and then buy a new one or not and enjoy !

Not sure what you mean by "battery manager" on the Equinox, but I don't think there is any function that does what you seem to think. Apparently there is some device or system in the Equinox that turns on & off and draws 3-4 amps. Modern vehicles have extensive electronics and are rather mysterious.

Are you sure you have followed the towing instructions under Recreational Towing in the owner manual? Most electronic functions are supposed to be disabled when towing 4-down.

As for the battery itself, once it has been run down to "dead" a few times, it is probably toast. Automotive starting batteries do not survive that very well. Especially if older.

Thanks for both comments.  I agree the modern cars have integrated electronics to the point that make mechanics hard to diagnose, let alone fix.  Will have the battery load-tested today. 

I hope that I am not posting too early, but it appears that my problem was simply my old battery.  Want to thank the responders to my problem post.  Both alluded to the same solution, which I followed up and had the 5 year battery checked and changed.

Unfortunately, I had to endure a lot of 'pecking' afterward from wife.  Checking out the battery first was her suggestion too!

We've all felt your pain.