1979 C3 - Power Drain, already replaced the convenience timer
05-26-2016, 06:37 PM
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Heel & Toe
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1979 C3 - Power Drain, already replaced the convenience timer
Last year I fixed a power drain by replacing the convenience timer with one that only has the lights on when the doors are open. Everything was fine until recently and I can't pinpoint just when the new drain started. I did have a bulb blow while pulling it out (driver side by my feet), but everything continued to work fine after replacing it.
I connected the voltmeter between the battery and the common cable and tested a few things. With the doors closed, there was almost no drain on the battery. I'm assuming it was the radio keeping itself alive. When I open the door, the drain goes way up as the interior lights kick on. I hear a 'click' of something turning on at the drive side fuse panel. When I close the door and the interior lights pop off, there is now a ~0.15 amp drain. I sat there for a few minutes to see if it would go away, but it didn't seem to want to. When I disconnected the battery and reconnected it to the voltmeter, the drain was gone again. It came back when I opened then closed the door though.
Any idea what it might be? I didn't think that level of drain was normal.
I connected the voltmeter between the battery and the common cable and tested a few things. With the doors closed, there was almost no drain on the battery. I'm assuming it was the radio keeping itself alive. When I open the door, the drain goes way up as the interior lights kick on. I hear a 'click' of something turning on at the drive side fuse panel. When I close the door and the interior lights pop off, there is now a ~0.15 amp drain. I sat there for a few minutes to see if it would go away, but it didn't seem to want to. When I disconnected the battery and reconnected it to the voltmeter, the drain was gone again. It came back when I opened then closed the door though.
Any idea what it might be? I didn't think that level of drain was normal.
05-27-2016, 10:18 AM
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Melting Slicks
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There aren't any relays at or near the fuse panel in a '79 so I don't know what you're hearing. Any chance that the sound is coming from the center console?
It almost sounds like the alarm system is activating but without the dedicated horn sounding. To test that theory first use the key to turn the driver side lock all the way counter-clockwise (unlocked). Then check for the power drain again. If it goes away, you've found the problem. If not, listen very carefully at the center console just ahead of the shifter--that's where the alarm relay is located. If you hear the click coming from there, disconnect the relay and it should get rid of your drain.
It almost sounds like the alarm system is activating but without the dedicated horn sounding. To test that theory first use the key to turn the driver side lock all the way counter-clockwise (unlocked). Then check for the power drain again. If it goes away, you've found the problem. If not, listen very carefully at the center console just ahead of the shifter--that's where the alarm relay is located. If you hear the click coming from there, disconnect the relay and it should get rid of your drain.
05-30-2016, 10:49 AM
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Heel & Toe
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There aren't any relays at or near the fuse panel in a '79 so I don't know what you're hearing. Any chance that the sound is coming from the center console?
It almost sounds like the alarm system is activating but without the dedicated horn sounding. To test that theory first use the key to turn the driver side lock all the way counter-clockwise (unlocked). Then check for the power drain again. If it goes away, you've found the problem. If not, listen very carefully at the center console just ahead of the shifter--that's where the alarm relay is located. If you hear the click coming from there, disconnect the relay and it should get rid of your drain.
It almost sounds like the alarm system is activating but without the dedicated horn sounding. To test that theory first use the key to turn the driver side lock all the way counter-clockwise (unlocked). Then check for the power drain again. If it goes away, you've found the problem. If not, listen very carefully at the center console just ahead of the shifter--that's where the alarm relay is located. If you hear the click coming from there, disconnect the relay and it should get rid of your drain.
05-30-2016, 12:30 PM
#4
Melting Slicks
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The key switch that arms and disarms the alarm system can be extremely finicky. When working properly the only way to arm the system is by locking the driver door with the key and the only way to disarm is by unlocking the driver door with the key. Neither the manual nor power locks are supposed to be able to arm/disarm the system.
If your problem continues and you're not concerned about alarm functionality, disconnect the alarm relay in the center console. Everything else will work fine and you won't have to worry about the relay coil draining the battery.
05-30-2016, 12:57 PM
#5
Melting Slicks
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I believe that key switch is a common source of aggravation and even rage 
Like with yours the alarm horn in my '79 had been disconnected--carefully. In addition the wires leading to the key switch had literally been ripped apart--likely because, like with you, the alarm system continued to drain the battery.
I think you can get to the alarm relay by simply removing the carpet panels at the console. If not, there is another way to disable the system if you don't want to dig deeper into the console.
Remove the panel under the steering wheel that contains the headlight override switch, then remove the A/C duct (it just presses on at both ends). There are a number of electrical connectors essentially stuffed up near the headlight switch. Find the four conductor connector with one light blue wire, one dark blue with white strip wire, one yellow wire and one black wire. Disconnect it and the system will be unable to arm.
BTW, the connector for the alarm relay has one orange wire, one yellow wire, one dark blue with white strip wire and one black wire.
Like with yours the alarm horn in my '79 had been disconnected--carefully. In addition the wires leading to the key switch had literally been ripped apart--likely because, like with you, the alarm system continued to drain the battery.
I think you can get to the alarm relay by simply removing the carpet panels at the console. If not, there is another way to disable the system if you don't want to dig deeper into the console.
Remove the panel under the steering wheel that contains the headlight override switch, then remove the A/C duct (it just presses on at both ends). There are a number of electrical connectors essentially stuffed up near the headlight switch. Find the four conductor connector with one light blue wire, one dark blue with white strip wire, one yellow wire and one black wire. Disconnect it and the system will be unable to arm.
BTW, the connector for the alarm relay has one orange wire, one yellow wire, one dark blue with white strip wire and one black wire.