Battery keeps dying - I believe it a Mach 460 amp drain. How do i 'disable' my amps?

[Q]

2001 Mustang Bullitt.
My battery will die after 3-4 days of not using the car. Replaced both the battery and alternator. Still happening. From online research, pretty sure my rear amps are causing the drain/death. I only use my car for weekends, and I don't care if it has a radio. How do I disable my amps so that this drain ceases? Is it a simple fuse, or more complicated?

Thanks.

 

[C1]

Wow, my daughter had a Bullitt too (dont recall the exact year), but it began exhibiting the exact same issue. It was some years back when I worked on it so dont remember the details, but I think that they are written up somewhere.

Here's what I remember:

Dont bother buying any batteries or alternators. What's going on is a about a 350-450ma current drain somewhere. The drain I measured & the battery run down over time matched super. So what happens is at the end of 4 -5 days of sitting the battery runs down to insufficient capacity to start the vehicle.

None of the shop people (including dealers) could fix it. They just wanna replace parts.

A warning is that I was never able to solve the issue. I parked the car in my garage & went over the electrical system with my VOM & did trace the majority of the current loss to a certain circuit, but never the specific component.

It is here that I dont recall the specific circuit, but Im thinking the radio was on that circuit. Right now Im thinking that the reason I couldnt analyze further is because I couldnt get under the dash or at least easily enough to take simple measurements at the component level.

I will look to see if I have my old notes.

A guess is that a dc current blocking diode or capacitor has broken down in some component (eg, radio or could even be a clock or something in the dash console equipments including gauges) and is the cause for the current leakage.

I think you can find the major circuit buy pulling fuses then jumper-ing one rail path or terminal set (using a wire with alligator clip at each end) and then inserting your amp meter into series with the other parallel rail/terminals (to complete the circuit).

Anyways, it's a bitch of an issue as nobody, including dealers, were of any help plus I never was able to pin the issue to the exact component.

If you find it, please let us know.

 

[Q]

Wow, my daughter had a Bullitt too (dont recall the exact year), but it began exhibiting the exact same issue. It was some years back when I worked on it so dont remember the details, but I think that they are written up somewhere.
.
.
If you find it, please let us know.

Very interesting, but also makes me scared now. Shit.

If my disabling of radio and amps don't solve the issue, I'm SOL I think and unsure what to do next. I guess sell the car, but how do you go about selling a car with that kind of asterisk? What did you do C1?

 

[C1]

Oh oh, I kid you not, my daughter was so frustrated that she got rid of the car. Traded it in at the dealer which didnt give her very much for it.

If I still have the history then it is on other hard drives which are at home.

Im at the public library now & it will shut me off in 15 min.

If you like the car then I would keep it & try to find the current leak.

As an interim measure, if the car is parked on the inside then connect a battery trickle charger up to it or if it's parked outside then you could patch in a portable solar panel that sits on the dash. Plug the solar panel into the cigarette lighter should do it.

Fry's Electronics sells stuff like that.

Another possibility is just pull either the fuse passing the current leak OR disconnect the negative battery terminal between use of the vehicle.

 

[mindless1]

Remember, online research is The Internet. You won't get the kind of accurate diagnostic that you or someone else would do in person.

Factory amps should have no parasitic drain when the vehicle is off, or at most some trivial low level sensing that wouldn't drain the battery in weeks. If this is an aftermarket install done by a cowboy, who knows!

The way to troubleshoot this is grab a multimeter, a couple alligator claw probe tips, and put it in series with the battery to measure current when the vehicle is off. When you disconnect the battery to do this, you want to have the multimeter probes already in contact with the battery cable and battery terminal so it does not cycle from battery disconnected to battery connected again through the multimeter, which may reset the battery saver timer to start counting down again for some time period before going into low power state. For other Ford vehicles around this era, I vaguely recall that the power saver time-out period was something like 40 minutes (at least a half hour but less than an hour I am certain of for other Fords with the battery saver circuit), but this too can be tested with a multimeter if, or once, everything is working right again. Ironic that a "battery saver" circuit causes higher battery drain. Progress?

Now, it may have random things like courtesy lights or whatever, that put the vehicle in a higher power state for some period of time after it is triggered. For example, merely opening the door to reach in and pop the hood release, might put it in a 200mA+ drain mode that doesn't settle down to tens of mA for over a half hour, and this is completely normal. On the other hand, a failed relay that handles the battery saver circuit can cause it to continue to drain at 200mA+ indefinitely.

With a multimeter in series you would pull out each fuse and relay in turn to see which change the current, narrowing it down to what is on that circuit.

IF it were that the amp is wired wrong to get constant battery current, that might be redone correctly. It is not the case that everyone with an aux amp has their battery go flat in 3 days. This can be fixed "somehow", the question is if the right person sees the right info to know what is going wrong.

 

[Yuriman]

If it turns out to be the amp, the fix is simple.

Most amps have 3 terminals - +12v, ground, and a sensor line to the head unit, that turn the amp on when it receives voltage. The +12v should be connected (through a fuse) straight to the battery, and will have little to no draw when the sensor line is cold.

If you find your amp is misbehaving, simply put an in-line switch on the +12v line to the amp (or the ground), and turn it off when you get out of the car.

 

[tracerbullet]

^ I was thinking the same thing.

I'd probably start by pulling the fuse, just to be sure that solves the problem, before making modifications in the wrong place.

I'd also, if it is the amp at fault, consider replacing the amp if an upgrade is available. I hate work-arounds, would rather solve the original problem. And as a car hobbyist I'd consider it a good excuse for an upgrade.

 

[Q]

Took it to Advanced Auto to test the battery, just to make sure it wasn't a lemon (got battery a month ago). Guy said battery seemed OK, but during the 5 min we were out there he tested it multiple times and said from beginning to end, it already dropped 3mA, which he said was a lot for that short time. (again, I have little knowledge on these mA readings so I took his word for it).

If you Google "mach 460 battery drain" there are many threads on many Mustang forums talking about either the radio wiring causing drain, or amps being bad causing drain:
http://www.stangnet.com/mustang-forums/threads/help-locating-a-battery-drain.810334/
http://www.moddedmustangs.com/forums/99-04/134698-battery-drain.html

So in Advance Auto's parking lot I just laid in my trunk and disconnected both 4pin power plugs from each of the rear amps. Will see if this solves anything - I'll wait 2 days and try and start the car...

Alternate idea:
http://www.allfordmustangs.com/forums/v6-tech/339235-2001-mustang-battery-draining.html

He talks of a fuse that may be always on...I don't want to pull a fuse and also unplug my amps, for if the issue gets solved then I won't know what caused what.

 

[C1]

Checked my HDDs at home for photos & notes.

Cant find any notes or emails, but - Yup, here's a pix I took of the daughter's Bullitt back in July 2001 after it was purchased early that year.

It's the same vintage 2001. She paid over $32K for that thing (I helped her).

It was a quite a few years later though when the subject issue came up.

The car was stock Bullitt & didnt employ any special radio/stereo assisting amps.

It was decent looking, but not particularly comfortable & man-o-man was the suspension firm/hard.
(Very hard riding.)

 

[mindless1]

Took it to Advanced Auto to test the battery, just to make sure it wasn't a lemon (got battery a month ago). Guy said battery seemed OK, but during the 5 min we were out there he tested it multiple times and said from beginning to end, it already dropped 3mA, which he said was a lot for that short time. (again, I have little knowledge on these mA readings so I took his word for it).

I don't know if it is you or that guy, but somebody is either mixing up terminology or incorrect. mA is a current reading and to have it drop only 3mA over multiple tests, is a VERY small amount of current decrease, so small that I don't even think the testing method could possibly, accurately discriminate that small an amount on the scale of hundreds of amps it should've been reading.

If it had instead dropped 3V, then yes that's a lot unless the testing was pretty brutal and long. All I'm really saying is the data you've conveyed is inconclusive, but weighing odds, to have one battery die and a replacement still have the same symptoms, is not likely, so yeah odds are the new battery is viable if it stays charged and there's a drain like you already suspected.

If you Google "mach 460 battery drain" there are many threads on many Mustang forums talking about either the radio wiring causing drain, or amps being bad causing drain:
http://www.stangnet.com/mustang-forums/threads/help-locating-a-battery-drain.810334/
http://www.moddedmustangs.com/forums/99-04/134698-battery-drain.html

So in Advance Auto's parking lot I just laid in my trunk and disconnected both 4pin power plugs from each of the rear amps. .

I still think a multimeter measuring current would help, for example if it's not the amp itself but damaged wiring or a stuck relay causing it. I mean disconnecting the amp may provide the short term solution to keep the vehicle operational, but when it comes time to know whether to replace an amp or something else, pinpointing the fault could save some time and money. Unfortunately I have other things that need attention so my time on this thread may be at an end.

 

[mindless1]

If it turns out to be the amp, the fix is simple.

Most amps have 3 terminals - +12v, ground, and a sensor line to the head unit, that turn the amp on when it receives voltage. The +12v should be connected (through a fuse) straight to the battery, and will have little to no draw when the sensor line is cold.

If you find your amp is misbehaving, simply put an in-line switch on the +12v line to the amp (or the ground), and turn it off when you get out of the car.

Keep in mind that a mere "in-line switch" may have to be a monster of a switch to handle enough current, depending on the amp rating.

This is another case where a multimeter might come in handy, to measure whether the sensor line (or audio signal path if activated by voltage on that), is behaving at 0V. If the amp is not receiving an input that should cause it to come on, it probably has a leaky if not failed shorted, transistor somewhere.

I suppose without a multimeter, merely unplugging the signal and/or sensor connection would do the same thing to check whether the amp is still drawing excessive current when it should be in off (deep sleep) mode, except that without a multimeter to measure that, you are still left waiting for eventual drain evidence of a dead battery, or lack thereof.

 

[crashtech]

A Bosch-style relay is your friend when switching high current. But that shouldn't be necessary, A competent technician should be able to track this kind of problem down in no more than a couple of hours, excepting any really serious disassembly work to access connectors.

 

[C1]

Ya, some competent tech might be able to locate & fix the problem, but dont be surprised when you get the bill for parts & labor (eg, cant image the cost of an instrument cluster part for such vehicle).

(One of the issues with Bullitt is that it wasnt possible, at least at the time, to install a larger capacity battery - simply no alternative available.)

An alternative is to mount a second battery in the trunk that is patched into the affected circuit. You dont need heavy gauge wire for this as the idea is that it's there to supplement the low current drain issue, not start/run the car. So, lighter gauge wire would avail current limiting for this purpose.

 

[mindless1]

A multimeter is free with coupon at Harbor Freight, or around $5 delivered on ebay, couple bucks more if a local seller so there isn't a month wait.

Not only can it measure current drain at the battery or anywhere else, it can also measure battery voltage while the vehicle is sitting, so you see how much the battery voltage decreases before it gets so low that you need a jump start or charger put on it.

 

[Q]

Update for those Googlers or anybody else: so far, it seems like I may have been correct and the amp(s) were draining the battery. I unplugged both rear amps, waited 3 days to try and start, and it fired right up. Drove it to work and back, waited another 2 days, and it worked again. Hope that is in fact, the issue. I will figure out whether I want to buy replacement stock amps on eBay, replace the entire system, or just leave it be since it is not my DD.

 

[sontakke]

My 1990 SHO had the same battery dying issue when it was new. After starting the lemon law proceeding, the dealer kept it for two weeks and had somebody from Dearborn come to debug it. Even he could not figure it out. Eventually, the technician noticed something warm in the trunk. It turns out the premium JBL amp was never turning it off when the car was off. New amplifier fixed it.

 

[mindless1]

^ Shows the disconnect between appropriate training and reality. It can take time, and wiring diagrams to find certain faults, but a tech "trained" for this should never have a case where they just can't FIND it at all, unless it's intermittent and they have too short a period of time to replicate the fault. Then again in a roundabout way, the fault was eventually found.

Personally, I would either find the fault IN the amp, repair it to a better state than it started out so that the failure isn't so likely to happen again, or replace it with something else. Buying something that has potential to fail again the same way does not appeal to me. Then again the original lasted 16 years? New old stock that lasted another 16 might not be a bad value, but I sure wouldn't buy a used pull that could fail the same way soon, unless it was very cheap and having a 2nd working unit helped to troubleshoot the circuit of the one that failed, but if you already have two of them and only one failed you don't need to buy another to do that.

 

[Q]

@mindless1 correct, I agree. If I do decide to fix this, I'll just rip out the entire Mach system and get everything replace. Costs a pretty penny, but it would allow me to get new speakers, etc as well. Mach system is good when it works, but from all the research I've done, it's a very odd setup.

Thanks everybody for the inputs.

 

[sontakke]

If you are DIY type, you can put a relay to the main power feed to the amplifier. You will be essentially remotely turn it on and off using the xternal relay instead of the one inside which we think is stuck on permanently or worse, randomly sticks on. Calculate the appropriate relay based upon the amplifier watts and do some hacking. The relay should be under $10 from Amazon.

But you better know what you are doing if you are going to take tha t route. Don't blame me if your car catches fire after you hack it