Battery Drain

[asemcken]

My 99 Windstar has become hungry for battery current when parked. I've already checked all the relays and fuses, but can't isolate any particular circuit in error. The battery is less than a month old, and the alternator seems fine (>14VDC when charging with very little AC ripple). Draw at rest bottoms out between 650 and 900mA - which seems way too high.

The dealer does not suspect the battery charging TSB, and I've already verified that all the interior lights do turn off when the doors are closed. The radio has come on and off a few times without a key in the ignition, which is my next place to check (going outside to pull the key switch).

Does anyone know what the drain is supposed to be at rest? I'm guessing somewhere south of 30mA. Any other ideas?

Thanks,
Adam

[12Ounce]

This subject was dealth with in depth on the old "cartrackers" forum. Now its in a catonic state. You can't even search there anymore.

Some posters found various current "killers". One that I do remember was wipers that weren't allowed to "rehome". Something in the way would prevent the wiper arm/mechanism from getting fully back to the start position ... and the wiper motor would stay loaded. But I would think that would cause higher currents than you are seeing.

I remember also one poster had a problem in his rear glass defroster.

Some had problems in the audio systems.

Some even attributed elect leaks to failing brake pressure switches (the ones on the brake master cyl). I don't know if this is even possible.

I'd start by pulling the "switched power relays" individually to see if that affects the current draw.

[asemcken]

Thanks for the points...

I've completed several hours' worth of measurements on the van and I think I have the culprit narrowed down...

Something still bothers me, it seems like the 'Battery Saver' circuit does not kick in until between 20 and 30 minutes of last use.

I measured V&I on the battery every 10 minutes and saw pretty even results (3/4A @ start of test, 575mA @ 10 and 20 minutes and 25mA @ 30 minutes) over almost all the relays. I also checked out each of the relays with a meter and came up with no huge items (some residue buildup which was polished away). Now, the #2 relay in the passenger compartment fuse block (top row, middle) is my suspect - with that relay in, the 30 minute reading climbed to a full ampere of current (versus 25mA). I need to track the circuits down that follow that relay. Off to the (horrible) Haynes manual - probably do better with the van's owner's manual for this.

Thanks again,
Adam

[asemcken]

The drain is definitely coming from something on the Delayed Accessory Relay (Relay 2 on the interior fuse panel).

I'm going to start with the obvious bits (remove the radio, which was acting funky anyway, take a look at the rear defroster) before I start tearing interior panels off and looking at window motors and the like.

Thanks for your input.
Adam

[12Ounce]

This relay is fed by fuse #106 (battery box). The coil is grounded by the ter #6 of the FEM. Some of the output load (mostly front windows) has no secondary fuse. Some load (radio, rear windows, window switch illumination) is protected thru fuse #18 (cabin junction panel).

[asemcken]

Finally found my power gremlin - the REM is toast... I gave in and spent the $$ on eBay for the diagnostics CD - it was a great help.

Of all things, it was the high-mounted rear stoplights. Here's the funny thing - they don't show up on the idiot light for burned-out bulbs, so I had no idea they were out until my wife followed me home one night. If anyone else has the same symptoms and gets to this point, check the resistance between the Tan/Blue wires on the high-mount bulb sockets and any real ground - if it's more than 10k Ohms, the REM has failed, and the high-mount stoplights never go off... My bulbs overheated so much the glass bubbled - I couldn't get one of the bulbs out of the lens assembly without a pair of pliers.

The REM's another $450 by the time it's programmed... I feel like I'm simply throwing money at the van to keep it moving....

On to a Honda?

Thanks,
Adam

[LeSabre97mint]

Originally Posted by asemcken

Finally found my power gremlin - the REM is toast... I gave in and spent the $$ on eBay for the diagnostics CD - it was a great help.

Of all things, it was the high-mounted rear stoplights. Here's the funny thing - they don't show up on the idiot light for burned-out bulbs, so I had no idea they were out until my wife followed me home one night. If anyone else has the same symptoms and gets to this point, check the resistance between the Tan/Blue wires on the high-mount bulb sockets and any real ground - if it's more than 10k Ohms, the REM has failed, and the high-mount stoplights never go off... My bulbs overheated so much the glass bubbled - I couldn't get one of the bulbs out of the lens assembly without a pair of pliers.

The REM's another $450 by the time it's programmed... I feel like I'm simply throwing money at the van to keep it moving....



On to a Honda?

Thanks,
Adam

Adam

What is a "REM"?

Dan

[asemcken]

REM = Rear Electronics Module - covers most of the electrical functions for the back end of the van. I'm not an automotive engineer, but I'm surprised that there would be an electronics module between the brake lights and the brake pedal. I would have thought that the lights would have been harnessed to power and the brake pedal switch for absolute reliability.

[asemcken]

Sorry - just parsed my reply - I made a cut/paste error in the diagnostics...

It should read :

...check the resistance between the Tan/Blue wires on the high-mount bulb sockets and any real ground - if it's more than 10k Ohms and the high-mount stoplights never go off, the REM has failed...

Apologies - should have proofread it before I sent it.

[OldFaithful]

I checked the Ford wiring diagrams on my 2000 Winnie and low and behold, the high mounted brake lights are connected to a hot circuit from the battery and that REM provides the ground for those lights.

The REM gets its command to provide that ground through another circuit with the brake pedal position switch (BPP) in it.

If the REM doesn't remove that ground, voli, dead battery. It is on a 20 amp fuse.

[asemcken]

Reading the Ford Tech Publication, I quote...

"Only the left and right stoplamps will provide lamp outage indication"

Which is how I missed the high-mount lights being on...

On mine, the Tan/Blue wire on C340 (connected to the left side of the REM when looking at it while mounted) never goes off ground, which led the high-mount bulbs to melt. Strangely, when the REM is removed, the battery saver circuit does not seem to engage...

[aviacionlight]

Hi, i have the same battery draining problem and checking this post find that the third lights lamps on my windstar 2001 are burned and the plastic´s melted, repplacing the lamps will solve the battery leaking problem? i will try.

Any updates?

Thanks
Angel Galicia