So, I'm still troubleshooting a few electrical issues in my car. Along with my tail lights lacking grounding, my car battery gets completely drained within a few days of sitting idle. This actually ruined my one-year-old battery. I've already purchased a new battery, but before installing it, I want to identify what's causing the drain.
Today, I had another opportunity to test my car since it was dry outside. I connected an amp meter between the positive terminal of the battery and the positive wire to measure the current. Upon connecting it, I heard a ticking noise coming from the front right side - I have no clue what caused it. Meanwhile, I noticed the current was around 8A. After the ticking stopped, the current stabilized at 2A. All of this occurred with the ignition turned "OFF". I disconnected the battery and repeated the process. Again, there was ticking for a few seconds, an 8A draw, and then when the ticking ceased, it settled at 2A. I repeated this a few times (2 or 3 times) until I no longer heard ticking upon reconnecting the battery. However, the draw remained at 0.8A consistently and didn't change. This is quite significant and would fully deplete my 70Ah battery in less than 4 days, which aligns with what I've observed over the past year.
I'm clueless as to what's causing this draw. Tomorrow, I plan to remove the fuses one by one and observe when the draw disappears. This should at least provide a starting point for further investigation.
Oh, and that brings me back to my original question: what amount of current draw is considered "normal"?
So, I'm still troubleshooting a few electrical issues in my car. Along with my tail lights lacking grounding, my car battery gets completely drained within a few days of sitting idle. This actually ruined my one-year-old battery. I've already purchased a new battery, but before installing it, I want to identify what's causing the drain.
Today, I had another opportunity to test my car since it was dry outside. I connected an amp meter between the positive terminal of the battery and the positive wire to measure the current. Upon connecting it, I heard a ticking noise coming from the front right side - I have no clue what caused it. Meanwhile, I noticed the current was around 8A. After the ticking stopped, the current stabilized at 2A. All of this occurred with the ignition turned "OFF". I disconnected the battery and repeated the process. Again, there was ticking for a few seconds, an 8A draw, and then when the ticking ceased, it settled at 2A. I repeated this a few times (2 or 3 times) until I no longer heard ticking upon reconnecting the battery. However, the draw remained at 0.8A consistently and didn't change. This is quite significant and would fully deplete my 70Ah battery in less than 4 days, which aligns with what I've observed over the past year.
I'm clueless as to what's causing this draw. Tomorrow, I plan to remove the fuses one by one and observe when the draw disappears. This should at least provide a starting point for further investigation.
Oh, and that brings me back to my original question: what amount of current draw is considered "normal"?
Normal is definitely much much less then that, like 0.03 amps or something, just enough to keep the ECM memory and radio clock.
What I can think of for the clicking is maybe something to do with the ventilation system? Do you have AC, if so you have the electrically controlled air box, I don't know if that is powered when the car is off, but it might make sense that it kicks back on for a few seconds to ensure it is in the right place when the battery is reconnected. I know a tape player can make some clicking sounds when reconnecting the battery, the headlights draw some amps and can click if they are the gen 1 system, that's a common battery killer.
How loud are the clicks, and how frequent, 1 per second, so fast as to be almost indiscernible as individual clicks, etc?
Definitely remove fuses one by one, have the multimeter hooked up, and monitor it as you remove the fuses, no need to disconnect the multimeter for each fuse. If you don't have a helper, use a phone to record the multimeter as you pull fuses, and set the phone up in the cabin, or the frunk to "listen" for where the sound comes from, and "watch" the knobs on the headlights, see if they move at all.
[This message has been edited by 1985 Fiero GT (edited 03-26-2024).]
What I can think of for the clicking is maybe something to do with the ventilation system? Do you have AC, if so you have the electrically controlled air box, I don't know if that is powered when the car is off, but it might make sense that it kicks back on for a few seconds to ensure it is in the right place when the battery is reconnected. I know a tape player can make some clicking sounds when reconnecting the battery, the headlights draw some amps and can click if they are the gen 1 system, that's a common battery killer.
No A/C, no cassette player. And I have Gen 2 headlights.
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How loud are the clicks, and how frequent, 1 per second, so fast as to be almost indiscernible as individual clicks, etc?
Loud enough you can hear them easily but not super loud. If I needed to guess, I would say about 5-10 clicks p/s. It sounds a bit when you try to start your car but there isn't enough juice in your battery. You hear it clicking too. Come to think of it, it sounds a lot like that clicking.
I wanted to record the sound on my phone but by the time I had thought of that, the clicking was gone. I know it will return tomorrow since so far, I have heard that sound each time I disconnect the battery for a longer time.
My battery was drained overnight a couple of times- why...? Was rebuilding the headlight motors- went up well but coming down one still wasn't right- tapped the knob on the motor and then it dropped....as I was leaving the garage I heard a ticking sound near that motor- looking around it I touched it- YOW! Hot....I unplugged it and the ticking stopped- later was showing a friend the headlight motors, explaining what had happened- did NOT turn the motors on or anything....Heard a ticking sound from the other side- ran around to that side and felt motor- just turned on all on it's own! Several Fieros have burned up because of these motors going bad
Disconnect the motors and see if you lose power on your battery again...That is probably your drain. I swapped in the later model (87-88) motor system- much better! (You will need the front light harness and the control module....and can buy new motors on Amazon)
Yeah, 8 amps then 2 amps is an awful lot when not running. Like others have said, maybe faulty headlamp motor. It's the only circuit that I can think of that is always powered so as to bring the headlights down even when you shut the car's motor off.
A stop gap method would be to put a battery switch in place or just disconnect the battery after driving. This would save draining the battery untill you find the fault.
I use a race car style cutoff switch that I turn off after each outing. There again, I can go several weeks (months) not using the Fiero.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
Disconnect the motors and see if you lose power on your battery again...That is probably your drain. I swapped in the later model (87-88) motor system- much better! (You will need the front light harness and the control module....and can buy new motors on Amazon)
or just disconnect the battery after driving. This would save draining the battery untill you find the fault.
That's my problem right there. I lost my trunk keys 2 months ago. So if I disconnect the battery the only way to get back in the trunk is to power the trunk release by connecting a battery through the cigarette lighter. But for that I need... a battery.
I moved my battery up front....but because it is under the spare tire, I have limited access- so I installed a battery disconnect switch- I can switch the battery off easily- just pop the front trunk and twist it. You could install a switch somewhere else, also (Although engine compartment/rear trunk would not be helpful...)
Try pulling fuses for things to see if that stops the drain- and definitely disconnect your HL motors for the time being- even the 2nd-gen ones can develop problems...
Loud enough you can hear them easily but not super loud. If I needed to guess, I would say about 5-10 clicks p/s. It sounds a bit when you try to start your car but there isn't enough juice in your battery. You hear it clicking too. Come to think of it, it sounds a lot like that clicking.
I wanted to record the sound on my phone but by the time I had thought of that, the clicking was gone. I know it will return tomorrow since so far, I have heard that sound each time I disconnect the battery for a longer time.
Maybe your headlights, I don't know exactly how the gen 2 system works, I would be inclined to think you have a grounding problem, somehow something isn't ground right, and the electricity is flowing through a "sneak path" as described in the ogre's cave, maybe somehow through the starter, making the sound, that would be intermittent as well, so might look for bad grounds
yes, max is ~ 35mA as standby for ECM Radio etc. Often uses Way less then max even w/ aftermarket "radios."
Over that will kill the battery faster, way faster > 1A. Just 1 194 bulb pulling ~ 0.29A can kill most batteries in a day or three. Remember a Starter Battery is functionally "dead" just ~ 11.9v...
Gen2 HL motor system should not kill your battery same reasons as Gen1 but if the module is "bad" then could have similar results.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I had the battery drain go on for awhile, and installed a race style interruptor ( Autozone) on the interior passenger firewall. Shut it off every time I finish driving it. Have not had a problem since.
My first guess would be the headlight motor(s). Second would be the fuel pump running. If the oil pressure switch sticks closed, it can run your fuel pump until the battery dies. You can test by unplugging your oil pressure sender. Or pull the fuel pump fuse. Either one should kill the pump, if it's running.
IMHO, 'bite the bullet' and buy the damn fastback trunk lock cylinder you found on eBay!
Well, I realized I don't have to. I can simply re-code the trunk lock cylinder with the lock tumblers from the "wrong" lock cylinder I had bought. Just need to find the time to do it (it requires drilling out a few screws since they were badly rusted and apparently had broken off).
You may have a couple of issues, in addition to the possible headlight motor issue, check to make sure the alternator isn't getting warm when the car sits for a bit. I've had a diode go bad and drain the battery overnight.
------------------ Rod Schneider, Ball Ground, Ga. "You can't have too many toys!" 1988 Fiero GT 1988 Porsche 928S4 1987 Corvette 2016 Mustang EcoBoost Van's RV-6 airplane
