Accessories Drain battery 99 Mustang
06-29-2014, 04:36 PM
#1
Thread Starter
Join Date: Jun 2014
Location: Ut
Posts: 2
Accessories Drain battery 99 Mustang
Hey guys, this has stumped me!
Charging circuit is working fine. I've tested the alternator a few times, all passes, as well as the battery. Alternator has already been replaced by the previous owner.
The problem with the car: Any accessory usage drains the battery while the car is on and off. If ignition is in the on position, anything you do will dim the instrument panel lights, and take power from anything else. Such as if I use the door and the windshield wipers at the same time, both will weaken. When the car is running, the Engine will shut off for a second if you do too much, before it kicks it self back on.
The charging circuit is putting enough power there, the voltage regulator is compensating correctly, but someone is draining it. Obviously its something in the interior of the car, maybe a short. No fuses have been blown, and we havn't seen any ground cables not tied down.
We've checked the GEM, PCM, no modules. No relays are stuck open. We've pulled everything but essentials, the drain still remains. A thing to note, the battery only drains while its on, to the point where the engine will die and shut off when stressed.
Any ideas?
Charging circuit is working fine. I've tested the alternator a few times, all passes, as well as the battery. Alternator has already been replaced by the previous owner.
The problem with the car: Any accessory usage drains the battery while the car is on and off. If ignition is in the on position, anything you do will dim the instrument panel lights, and take power from anything else. Such as if I use the door and the windshield wipers at the same time, both will weaken. When the car is running, the Engine will shut off for a second if you do too much, before it kicks it self back on.
The charging circuit is putting enough power there, the voltage regulator is compensating correctly, but someone is draining it. Obviously its something in the interior of the car, maybe a short. No fuses have been blown, and we havn't seen any ground cables not tied down.
We've checked the GEM, PCM, no modules. No relays are stuck open. We've pulled everything but essentials, the drain still remains. A thing to note, the battery only drains while its on, to the point where the engine will die and shut off when stressed.
Any ideas?
06-30-2014, 12:05 PM
#2
Still sounds like a charging problem. The alt might be testing fine but somehow the battery isn't taking the charge. How are you testing the alt? Once the car is running you should be able to unhook the battery and the alt keep the car running.
If not and you're POSITIVE the alternator is good then you have a wiring issue somewhere or a bad battery.
The battery starts the car, once running the alt supplies juice to everything and charges the battery.
If not and you're POSITIVE the alternator is good then you have a wiring issue somewhere or a bad battery.
The battery starts the car, once running the alt supplies juice to everything and charges the battery.
06-30-2014, 09:10 PM
#3
Thread Starter
Join Date: Jun 2014
Location: Ut
Posts: 2
Definitely not the battery, once removed while running still exhibits the same problems. A thing to note,when using any accessory in the car, the instrument panel lights fade, as well as any accessory slows down(power loss to everything), the one thing that doesn is the Battery Indicator light on the dash panel, which seems to come straight from the alternator, so another indicator that it works fine.
We've tested with all the relays out, and fuses pulled one by one. Can't seem the pinpoint it. Our car scanner indicates no problems with the GEM, or PCM. Any where you'd think to check?
We've tested with all the relays out, and fuses pulled one by one. Can't seem the pinpoint it. Our car scanner indicates no problems with the GEM, or PCM. Any where you'd think to check?
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