Battery drain and crazy issue when charging battery

[natanic]

Hello, I'm new to this forum, but have a very weird issue, and hopefully someone can offer some assistance. I have a 2000 Explorer with 4.0. A couple months ago, it started over heating, and assume my thermostat was bad, so got it back home and parked it. Have another vehicle, and haven't had time to tend to the Explorer until a couple weeks ago. I went to try starting it, but the battery was dead. When I put the battery charger on it, the meter on my charger went about half way up for a second, then jumped all the way up very quickly, while the door chime inside the truck was chiming, and this continued on off and on about every second. It seems that something is causing a strong electrical drain, but doing so in fluctuating manner, roughly every second. It never holds a constant draw and I didn't leave the charger on, in hopes that I did not make the problem worse. I replaced the battery with a new one, and charged it before installing in the truck. Once I connected the 2nd battery terminal, it did the same thing. I can hear a contactor, or something, clicking in the air box area, on the left side of the engine. Anyone ever seen something like this, or have any advice? Thanks!

 

[firepop5]

Sounds like a relay in the power distribution box is opening and closing. Put your finger on one at a time to see which one it is and you'll know which components to check.

 

[2000StreetRod]

driver's side?

. . . I can hear a contactor, or something, clicking in the air box area, on the left side of the engine. . .

By "left side of the engine" do you mean the driver's side?
My "air box" do you mean the power brake booster?

 

[natanic]

Thanks for the advice.

Sorry, by left side, I meant the passenger side. And by "air box" I mean the air cleaner, not power brake booster. Thanks

 

[2000StreetRod]

which engine?

There were two 4.0L engines in 2000: OHV and SOHC V6s.
There is an Auxiliary Relay Box below the air filter enclosure.

It contains the high speed blower relay, fog lamps relay, front washer pump relay, air suspension control relay and the rear washer control relay. You might make sure all of those functions are off.

 

[natanic]

Thanks! It's dark when I get home after work now, so I haven't been able to look over it very good yet. But, I think it's a SOHC.

 

[Greg_DonWindsor]

It is also possible you may have a dead short in a wire somewhere, though more than likely relay related.