I recently replaced my battery. After a really cold night out doors in Feb, my truck wouldn't start without a jump. In the weeks after that, it started more and more sluggishly every morning until it wouldn't hold a charge over night. So I put the biggest Optima Yellow Top (D34/78) in about a week ago. And everything seemed fine.

This morning, the battery is dead enough that absolutely nothing works. I jump it and check that I didn't leave anything on that I shouldn't have. Absolutely nothing looks out of order. But I noticed that I hade the front defrost switched on on the climate control since it was rainy and humid out last night when I was out. I rarely have this turned on and it occurred to me that on the cold day when my factory battery met it's demise a month ago, I had had the front defrost on too.

So I assume I've got some sort of parasitic draw and will take the H2 into the dealer in the very near future. And I'm sure it'll be there for weeks while they try to figure it out

But being curious is there some relay that's getting opened and maybe sticking open when you depress the front defrost setting on the climate control? Note this is the front defroster and not the rear defogger which would give me obvious candidates for bad relays. As far as I can tell there's not obvious relay on the front. Might it be the A/C COMP RELAY in the engine compartment fuse box?

I don't have an aftermarket stereo. But I have heard something that sounds like a faint periodic (every ~30 seconds) clicking in some of the speakers with the vehicle off and stereo off but when RAP power is still in effect. So perhaps my stock stereo is still to blame even though it's supposedly wired up right.

I was under the impression that in most reasonably sophisticated vehicles, when you activate front defrost the air flow is redirected. But also, if it's warm enough, the AC compressor is activated to help condense excess humidity in the supply air. I'm just wildly speculating about this though since the front defrost switch is the only thing I've observed to be coincident with these battery failures especially since I almost never have it activated.

Disconnect + side of battery, insert current meter in series with battery lead and battery + terminal. Check for crrent draw on meter. If there is some detected, start removing all fuses and relays - one at a time until the current drops down significantly.

Once you find the fuse/relay that causes the current draw problem, you can hopefully quickly locate the problem.

If this turns out to be a very repeatable thing, I might give an ammeter a try. But I'll probably relinquish it to the dealer,as much as I hate to do that, to figure out since it's still under warantee.

BTW, sometimes these problems turn out to be that the total current is caused by multiple devices and can be working properly. Good luck...

Try removing the "AMP" fuse in the under hood fuse box and let it sit overnight see if the battery still drains. Have had issues with the staying powered up and killing batteries. If that doesn't work try again removing the "HVAC" fuse have also seen instances of the hvac module staying awake causing a high draw.

Re: Dead battery, again ... locating parasitic draw
 

Well it happened again :mad: Saturday was very humid and drizzly. I had the defrost on to reduce fogging. Sunday morning, dead battery. I'm 99.9% confident that it's related to the defrost and humidity now.

It's going to the dealer for other stuff. I guess I'm going to have to give it up for a long time for them to be able to reproduce and diagnose...or maybe I should never turn on the defrost again.

Re: Dead battery, again ... locating parasitic draw
 

Did you ever get this resolved? I had my OEM battery die on Thursday of last week, so I mindlessly replaced it with an Optima. Now, 3 days later, the Optima is dying. Any help would be greatly appreciated.

-Pete

Re: Dead battery, again ... locating parasitic draw
 

Nope. I've had one more mysterious dead battery since May, but that's it. It's so spurious that I've just decided that I'll live with the deep cycle battery + jumper.

If it's happening regularly for you, take it in. If it's no longer under warranty, you're concerned about the cost of diagnosing it, and you have some educated guess about what system might be the culprit, it might be worth investing in an ammeter. Wire it into your + terminal hookups and note the discharge rates at periodic intervals times while the vehicle is off. I'll look in my manuals for in-spec current's to expect (no promises I'll find the numbers). Then if you seem something larger than those, start pulling fuses in the systems you think might be to blame until the current measured by the ammeter drops to expected levels.

Re: Dead battery, again ... locating parasitic draw
 

Don't know if this helps, but the last time my battery died completely, I had noticed some of the instrument lights were on - The odometer reading, and a couple of panel lights to the rear seat heater and radio controls. That was it. We were camping, and had the interior lights set to 'off' with the rear hatch open for quite some time. When I went to close the hatch is when I noticed those lights. I figured they would turn off by themselves...but in the morning, the vehicle was completely dead.

Re: Dead battery, again ... locating parasitic draw
 

Yep, took it in this morning. We'll see.

Thanks,

Pete

Re: Dead battery, again ... locating parasitic draw
 

Sorry to get in here late. Most likely they will tell You a faulty front passenger seat adjustment switch. I do not understand why there has not been a recall on these. It seems if you have a passenger and they adjust seat the switch will be stuck in a closed position and draw current for 2 or 3 days and if not driven daily battery will be dead. I worked with my dealer on this trying different things to help them have an answer. They suspected it but, i played with it by wiggling the switch after shut down of engine and other things. I finally confirmed that it was seat switch they changed out and never had a problem a gain.

But, I do know others on this forum have found other things that caused problem. My dealer for 2 years now have found this to be the problem most of the time not always.

TAZ

Re: Dead battery, again ... locating parasitic draw
 

Sorry to get in here late. Most likely they will tell You a faulty front passenger seat adjustment switch. I do not understand why there has not been a recall on these. It seems if you have a passenger and they adjust seat the switch will be stuck in a closed position and draw current for 2 or 3 days and if not driven daily battery will be dead. I worked with my dealer on this trying different things to help them have an answer. They suspected it but, i played with it by wiggling the switch after shut down of engine and other things. I finally confirmed that it was seat switch they changed out and never had a problem a gain.

But, I do know others on this forum have found other things that caused problem. My dealer for 2 years now have found this to be the problem most of the time not always.

TAZ

Re: Dead battery, again ... locating parasitic draw
 

Thanks Taz, I'll pass that along to them. They've charged the battery and keeping it overnight to see if the problem repeats. I guess they have to rule out a weak off-the-shelf battery first.

Re: Dead battery, again ... locating parasitic draw
 

Someone else already mentioned the same problem I'm having- sometimes when I turn off the ignition and take out the key, the shift position indicator will still be lit and a red battery light is displayed.

It's not a big deal to cycle the key again and it goes off, but if anyone else drives it, there is a risk they'll kill the battery if they don't notice it.

It's out of warranty and I mentioned it to the dealer while in for other service, he said it needs adjustment :confused:

I recall seeing a TSB about ignition switches, but I'll be damned if I can find it.

Re: Dead battery, again ... locating parasitic draw
 

When I took mine in a few weeks ago, they supposedly couldn't find any problems. They put a charger on the new Optima battery overnight, thinking that maybe the battery was just weak from sitting on the shelf. Whatever. It took about two weeks, but the battery is drained again. When I called this morning to schedule an appointment, the service manager is already pointing a finger at my non-dealer-installed DVD headrests. Anything to keep it from being claimed under warranty, I guess. :rant: Taking it on Wednesday.

Re: Dead battery, again ... locating parasitic draw
 

Okay, just got a call from my service guy saying that they replaced the (brand new) Optima Yellow Top, and that my problem was that that battery did not have enough cold cranking amps for my truck. Does that make any sense?