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On my '72 Supreme with 4 way power seat, I've noticed lately that sometimes when I get it, the courtesy lights will flicker off and then come back on. Also, my battery drained while parked for a couple days. Bought a new battery and installed it today. Started it up and checked the alternator..all good. Shut it down, and checked the battery 2 hours later, and it dropped to 72%...yikes. So I'm thinking the issue is in the wiring for the seat since that I'm only having issues with the courtesy lights when I sit down. If I disconnect the power seat switch, would that stop the parasitic drain?
Sounds like you need an exorcist as the 2 circuits have nothing in common.
Well, that eliminates the seat switch. Do the wires for the courtesy lights run under the front driver seat? I'm thinking maybe the weight of me sitting down is causing a chafed wire to short, causing my lights to flicker..maybe? But then again, once Im sitting down, everything is fine.
Ok..so I just checked the battery again after sitting for 3 hours..went from 72% to 70%, but when I first installed it around 1 pm today, it went from 100% to 72% in two hours...????...
You have 2 chocies first get a battery quick disconnect and ignore the drain or rip your hair out for the next 6 months while cursing your multi meter.
Truthfully the battery quick disconnect is a good idea idea anyway. I use mine every time I turn the car off in the garage. Cheap insurance.
Hook a test light in series with the negative cable and the battery. See if the light is lit. If it is then start pulling fuses until the light goes out. When the light goes out, that is the questionable circuit. If the light is not lit for the test, either the battery needs charging or it's bad.
The lights flickering when you sit is odd, but if they only flicker when you're sitting its likely not your drain. The harness does run under the seat but it should be pretty well strapped to the floor and far from seat bottom.
I like to skip the test light and hook a meter in series on the amperage setting. The very first thing I do is disconnect the harness at the firewall plug while watching the meter. This will immediately tell you if the draw is under the hood or in the car, or at least gets power from inside the car. If you pull that plug and the amperage doesn't drop at all you know the draw is either in the generator, starter or the regulator.
If it doesn't, well then you are in for more digging. I've had luck laying under the dash while having a helper tap the battery cable making a quick connection over and over. You may hear a relay click or slight hum from something. This method bailed me out with a 77 Corvette that had some car alarm installed in the 80s. The owner had no idea it was there but it was pulling the battery over a few days.
Hook a test light in series with the negative cable and the battery. See if the light is lit. If it is then start pulling fuses until the light goes out. When the light goes out, that is the questionable circuit. If the light is not lit for the test, either the battery needs charging or it's bad.
Exactly. The use of a volt meter will help also. The test light is a very simple test of current draw.
Hook a test light in series with the negative cable and the battery. See if the light is lit. If it is then start pulling fuses until the light goes out. When the light goes out, that is the questionable circuit. If the light is not lit for the test, either the battery needs charging or it's bad.
this is way I do it also. Think on what you have that is suppose to pulling power with the car off, for example do you have a clock or an aftermarket stereo (that has memory), so pull that circuit first.
Hook a test light in series with the negative cable and the battery. See if the light is lit. If it is then start pulling fuses until the light goes out. When the light goes out, that is the questionable circuit. If the light is not lit for the test, either the battery needs charging or it's bad.
God, the good old days using a test light. Consider yourself lucky, this is good advise. Start with the light in line and pull fuses one by one. I have seen a relay cause a draw so if you have one somewhere for something, try pulling it out as well and lastly I have seen a voltage regulator cause a draw as well. I had to chase a draw on one of my more modern cars and it involves putting modules to sleep, checking the draw in Milliamp range. You got this.
Sounds like you need an exorcist as the 2 circuits have nothing in common.
Here's another thought...what if the seat relay is causing the drain, and the lights are flickering because the seat relay is drawing power on the entire electrical system? Is that possible?
Here's another thought...what if the seat relay is causing the drain, and the lights are flickering because the seat relay is drawing power on the entire electrical system? Is that possible?
Does the seat move on its own? If not it's not a relay.
Something else that's troubling me is when I checked the old battery yesterday, it only showed 43% charged after driving it for 30 minutes, and that's why I thought it was bad. When I swapped it out with a new one, put the old one on a charger, and tested it once fully charged..100% charged and good battery was the result. Checked it again about 6 hours later, same result. So I checked it again this morning, and it only dropped to 95% after sitting all night. Yet, I have three indicators that the alternator is good: 1)I disconnected the negative terminal while it was running, and the car didn't shut off. 2)My alternator gauge is reading a steady 13.5-14 volts, and 3) A hand held tester said all was good.
So, why did the old battery only read 43%?...I don't understand ???
Use caution when connecting an ammeter in series to the battery. The battery discharge rate (parasitic draw) you describe may indicate a high current flow that can damage your DVOM. Most digital meters are 10 amp max. Anything higher will immediately blow a expensive ($36 for my Fluke DVOM) internal fuse.
I suggest start by using a test light in series with the negative battery terminal and cable as described in post #8. Just remember to disconnect then reconnect the test light after you pull each fuse or disconnect a component or wire harness. The suggestion to disconnect the bulkhead connector may be helpful. The alternator and the voltage regulator suggestion are also good. Disconnecting each one first (alternator then the VR) would be the easiest way to start. After that I would repair the known electrical issue you describe - the courtesy lights issue. Chasing down a parasitic draw while ignoring a known electrical issue is not a good diagnostic game plan. If you don't already have a factory wiring diagram and an electrical component locator make that step one. Step two would be to study the courtesy light circuit including all switches and the wiring harness routing. Step three would a visual examination of all wiring, switches, lamps, and sockets for damage or modifications (oh, there's a hot lead!) that may have be made over the last 50 years.
Do your circuit examinations and tests, ask questions here and keep us posted with your progress. If you need help, please PM me. I'll do my best to walk you though if need be.
At the risk of being Captain Obvious, have you checked to ensure the under hood light, map light, trunk light, and glove box light are actually turning off when they’re supposed to be off?
I’m asking because on more than one occasion I have inadvertently turned on the mirror map light or the dash map light while wiping down the interior and didn’t see that it was on due to the bright daytime sunlight.
At the risk of being Captain Obvious, have you checked to ensure the under hood light, map light, trunk light, and glove box light are actually turning off when they’re supposed to be off?
I’m asking because on more than one occasion I have inadvertently turned on the mirror map light or the dash map light while wiping down the interior and didn’t see that it was on due to the bright daytime sunlight.
Well, I have the hood light wired to a toggle switch, and I know the glove box light and trunk lights are turning off, and I'm pretty sure the map lights are off.
So I checked the voltage on the battery tonight and got 12.3 volts. According to my research, that equates to just over 75% charged. Not great, but it's actually better than the 72% I had when I left work yesterday, and it's been sitting since I got home last night. So for now I'll just keep an eye on it and see what happens.
Checked it again today..still 12.38 volts..checked my old battery and it was 84% at 12.5 volts. I also checked 3 other batteries in the store...92% at 12.58, 89% at 12.58 volts and 75% at 12.4 volts respectively. This should put me around 72%ish which is what it was Saturday. I dunno if the problem still exists, but my battery is holding steady.
Put the battery on a charger and get it to 100%, usually comes out to 13.2ish volts and settles to 12.6. Most shelved batteries will not be charged to 100%, they lose voltage from sitting.
Put the battery on a charger and get it to 100%, usually comes out to 13.2ish volts and settles to 12.6. Most shelved batteries will not be charged to 100%, they lose voltage from sitting.
I realize this..I was only trying to get an estimate of the charge on my battery by comparing it to other batteries at various levels of charge
Checked the voltage on the battery again last night...still 12.3 volts. Hit the key today to go to the car show and she fired right up. I checked the voltage once I got to the show and it was 12.6. After being at the car show for 5 hours with my trunk open and the trunk light on, no issues when I got ready to leave. Also, I noticed that since I swapped the battery out, the clock is keeping perfect time. I did nothing but change the battery, so I have no idea, but I'm calling it good.
So it seems my woes still exist. I checked the battery voltage today and it was down to 11.3 volts. I also hooked up a test light in series on the negative side of the battery and it lit up. Time to dig deeper, but in the meantime, why would I have an intermittent drain? Seems to me it would either be all the time or not at all, correct?
So it seems my woes still exist. I checked the battery voltage today and it was down to 11.3 volts. I also hooked up a test light in series on the negative side of the battery and it lit up. Time to dig deeper, but in the meantime, why would I have an intermittent drain? Seems to me it would either be all the time or not at all, correct?
Best SWAG - you have a ground issue &/or loose nut/bolt located somewhere along the ground path. You know the story, remove each ground point wire, check the end terminus of each wire, clean both the end terminals and the metal with abrasion (sand paper, wire brush, etc.).
Finally, I have had this happen on many various vehicles e.g. motorcycle, lawn mowers, vehicles, etc. Check the integrity of the (most often ground) wires - but, it can sometimes be the positive (+) wire(s) for tell-tale blue/green corrosion/oxidation. Take a very sharp utility blade knife, cut a slice into the wire(s) from one end and check for the build-up of green/blue "gunk". The more gunk you have the greater the alternator will work to replenish needed electrons. It may be working so hard to overcome the resistance (build up of "gunk") you never get to the point of replenishing electrons. Those wires don't last forever.
This is what can lay covered up under the protective insulation of a positive or negative wire - a solid build-up of "gunk" which you won't see unless you remove some of the insulation and reveal the culprit. Electrons do not flow through "gunk", and the resistance can increase significantly until you can't supply electrons to recharge the battery.
So it seems my woes still exist. I checked the battery voltage today and it was down to 11.3 volts. I also hooked up a test light in series on the negative side of the battery and it lit up. Time to dig deeper, but in the meantime, why would I have an intermittent drain? Seems to me it would either be all the time or not at all, correct?
Before you hook up the test light, establish what you have that is suppose to pulling power when the key is off. For example do you have a clock or and radio with memory, etc. Is so, unplug those first.
This is what can lay covered up under the protective insulation of a positive or negative wire - a solid build-up of "gunk" which you won't see unless you remove some of the insulation and reveal the culprit. Electrons do not flow through "gunk", and the resistance can increase significantly until you can't supply electrons to recharge the battery.
why would I have an intermittent drain? Seems to me it would either be all the time or not at all, correct?
No, not really. There are things can cause intermittent issues, such as a wire with insulation rubbed through which makes contact (shorts) sometimes due to vehicle motion / vibration.
Before you hook up the test light, establish what you have that is suppose to pulling power when the key is off. For example do you have a clock or and radio with memory, etc. Is so, unplug those first.
Just a clock, but that's supposed to be a constant draw.
No, not really. There are things can cause intermittent issues, such as a wire with insulation rubbed through which makes contact (shorts) sometimes due to vehicle motion / vibration.
A short to ground would kill the circuit, wouldnt it? Because everything is working.
April 2nd, 2022, 01:24 PM
