found bat drain source, need wiring help

[SaleenGT2001]

i hooked up the meter to my car today and found with the key off and the doors closed it is pulling 0.20 amps. i dont know if this is a lot but i know my battery dies every 5 days or so. i tracked the problem down to 2 seperate sources. the #3 maxi fuse under the hood (starter relay, ignition switch) is pulling .05A. the other drain is coming from the #39 fuse inside the car. it is a 5A fuse and it is labeled GEM. it is pulling .15A with everything shut and no key in the ignition. i let the car sit for about an hour before tracking anything down and the door was open but the latch was in the closed position so the interior light was not on.

with both fuses pulled there is no drain on the battery.

can someone help me out with the next steps to getting rid of my problem??

 

[san~man]

.20A is a lot of drain, even though it doesn' t sound like it is.

 

[SaleenGT2001]

i need to find out what the GEM runs. i know the mach 460 amps are sometimes the problem, but how can i check them??

 

[BobHyatt]

it isn't that much

.20A is a lot of drain, even though it doesn' t sound like it is.

.2 amps per hour = .2 * 24 = 4.8 ah draw per day. No way that will crash a good battery in 5 days. A good battery has well over 100ah capacity, which would last 3 weeks at that draw, and really much more.

200 milliamps (.2 amps) is a significant drain however. You could always start pulling fuses and see which one(s) result in a significant current draw decrease. I'd think 20-30ma is a more reasonable value to keep the computer's memory up and the stereo stations and so forth in memory.

 

[Mstg05]

The GEM is everything basically. I should say, almost everything runs through the GEM. By pulling the fuse for the GEM, you really havn't narrowed anything down. Do you have an aftermarket alarm on the car? If so, you need to pull the relays, the fuses, the connectors first before you start pulling your hair out. Batt. drains can be a HUGE pain in the butthole.

 

[SaleenGT2001]

yes i do have a viper alarm. it will be coming off wednesday!
\

 

[Mstg05]

Let me know how it works out. THe only reason I suspect an alarm is that, awhile back, I had a windstar at work with the same problem, same draw too. The dealership I work at very rearely sees mustangs with serious problems, such as batt. drains. Although, we have had 2 newer (s197) stangs with batt. drain problems. I did not work on either so unfortunetly I couldn't tell you what was wrong.

 

[jeffnoel]

Sorry for the intrusion but how do you test for battery drain? What type of meter do I need?

 

[BobHyatt]

Sorry for the intrusion but how do you test for battery drain? What type of meter do I need?

Most VOMs (volt/ohm/milliampmeter) can do it. Some are limited to very small current draw ranges, some can measure up to 10 amps for short periods of time.

milliamp = .001 amps, so you need something that can measure a current more than what you expect to deal with... 10a is pretty good although a starter can pull 10x that, as one example.

 

[04sonicblueGT]

it is highly unlikey that the alarm is an issue. If there is an issue with the viper, they have life time warranties on there brains so if it is an issue they will send you out a new brain. But i can say in 8 years i have seen 1 alarm that had a drain issue.most of the time is it an install issue or a bad relay if the alamr is the problem. i wouldn't get the alarm ripped out just to find out if it is the problem. The GEM module is going to pull some power all the time. Our cars computers do not totally turn off when the car is off. It runs a cycle every 30 mins or so. what other aftermarket electronics do you have in your car. radio amps guages ????

 

[jeffnoel]

I have a multimeter were do you put the probes to check for drain?

 

[twogts4us]

For what it's worth at this point GEM=GENERIC ELECTRONIC MODULE
I was curious, saw it in the manual and looked it up...

 

[Mstg05]

it is highly unlikey that the alarm is an issue. If there is an issue with the viper, they have life time warranties on there brains so if it is an issue they will send you out a new brain. But i can say in 8 years i have seen 1 alarm that had a drain issue.most of the time is it an install issue or a bad relay if the alamr is the problem. i wouldn't get the alarm ripped out just to find out if it is the problem. The GEM module is going to pull some power all the time. Our cars computers do not totally turn off when the car is off. It runs a cycle every 30 mins or so. what other aftermarket electronics do you have in your car. radio amps guages ????

I've been in a dealership 2 years and some months, have seen it twice. They where on the other hand cheap alarms. Just cause it says viper doesn't mean anything, a relay is a relay and they can all go bad. You don't have to rip out the alarm, just disconnect it and the relays.
Yes the GEM does pull a draw, but not all the time, it will go to sleep. Hence why the ford shop manual says to wait 40 mins for everything to time out.

 

[Mstg05]

Just figured I'd get some info for everyone...straight from the shop manual:

Battery—Drain Tests

NOTE: No production vehicle should have more than a 50 mA (0.050 amp) continuous draw.

Check for current drains on the battery in excess of 50 milliamps (0.050 amp) with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure:

CAUTION: To prevent damage to the meter, do not crank the engine or operate accessories that draw more than 10A.

NOTE: Many modules draw 10 mA (0.010 amp) or more continuously.

NOTE: Use an in-line ammeter between the battery positive or negative post and its respective cable.

NOTE: Typically, a drain of approximately one amp can be attributed to an engine compartment lamp, glove compartment lamp, or luggage compartment lamp staying on continually. Other component failures or wiring shorts may be located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading will fall to an acceptable level. If the drain is still not located after checking all the fuses, it may be due to the generator.

1-Make sure the junction box/fuse panels are accessible without turning on interior and underhood lights.
2-Drive the vehicle at least five minutes and over 48 km/h (30 mph) to turn on and exercise vehicle systems.
3-Allow the vehicle to sit with the key off for at least 40 minutes to allow modules to time out/power down.
4-Connect a fused jumper wire between the negative battery cable and the negative battery post to prevent modules from resetting and to catch capacitive drains.
5-Disconnect the negative battery cable from the post without breaking the connection of the jumper wire.
NOTE: It is very important that continuity is not broken between the battery and the negative battery cable when connecting the meter. If this happens, the entire procedure must be repeated.

6-Connect the tester between the negative battery cable and the post. The meter must be capable of reading milliamps and should have a 10 amp capability.
NOTE: If the meter settings need to be switched or the test leads need to be moved to another jack, the jumper wire must be reinstalled to avoid breaking continuity.

7-Remove the jumper wire.
NOTE: Amperage draw will vary from vehicle to vehicle depending on the equipment package. Compare to a comparable vehicle for reference.

8-If the draw is found to be excessive, pull fuses from the battery/central junction box one at a time and note the current drop. Do not reinstall the fuses until you are finished testing.

9-Check the wiring schematic in the wiring diagram for any circuits that run from the battery without passing through the battery/central junction box. Disconnect these circuits if the draw is still excessive.

 

[04sonicblueGT]

the computer wil not totally go to sleep. it will still runs is cycle. i am positive on the time. IF it does actually totally go to sleep it takes more than 24hrs. Only reason i am sure of this is that when the computer runs its cycle if the alarm is not properly connected it will be tripped by that cycle. and i have seen it happen after a car has sat over night.

And yes a relay is a relay but there are differences in quailty which would effect reliablity. like i saide the Alarm will not likely be a problem but a relay that is connect to the alarm can be.

not trying to argue, mstg05 are you in the shop or just saying that the mechanics have said the alarm was the problem? not that it couldn't happen especialy with those flee market alarms. but it isn't uncommon for dealerships to blame aftermarket equipment when they can't figure out the problem.

 

[mineralgraygt]

ford recomends to let the vehicle sit for 45 mins to an hour to let modules sleep then i hook a dmm inline between the negative battery cable and the actual battery post leaving the dmm off since it will still tranfer the the power turn the power on when your 45 mins is up and it will read a draw .05amps is aceptable over that you have a problem

 

[Mstg05]

Yes I am in the shop. I worked on one of the vehicles I mencioned in the previous post. I understand where your coming from saying dealerships blame aftermarket components, but to look at it this way: (i'll use alarms as an example) Aftermarket companies are not going to make a different model alarm system for every make of car, its generic, so different cars may react in different ways. I'm not going after the alarm saying it is the problem, i'm simply reccomending that it be disconnected for purposes of ruling it out. I lost my ass on a similar problem. Like I said, it was a windstar with an aftermarket "flea market" alarm. When I pulled the fuse for the GEM (just like in this case), my draw dissapeared. It would take about 3 days for the battery to die, so I disconnected the alarm and relays, and after doing so, have not had a problem since. Car has not been in for that problem in the past couple months, and still comes in for regular service.

Being in the dealership (previously employed at an independent shop), I see alot of aftermarket components that are to blame. Not just alarms but things from batteries and brakes, to gaskets and filters, ect. Car manufacturers don't reccomend dealership service to rip people off, they reccomend it because the simple fact of the matter is that OEM parts are best 99.9% of the time. They are manufactured for a specific make, and model. People can say what they want about dealership service, its their right, I was one of those people that called them "stealerships" but working for ford has proven the fact that the serivce department is there for a reason. Hell, even if I owned a toyota, i'd be taking it there for service, or picking up my parts from a toyota dealer.