Clock on = Drained Battery??? (1 Viewer)

[newsomew]

I purchased an 89 LC earlier this year as a project truck. I crank it about once every 2-3 weeks. The battery is always dead. One thing I noticed that I haven't noticed before is that the clock stays on regardless if the truck is running or not. Is that common? How can I get it to turn off when the truck is off?

 

[Benjaman]

With the truck off, there should be a 15 ma draw. More if you have an alarm.

 

[2mbb]

the clock needs power to keep the time. However, if it is working properly, the clock display will go out when the key is turned to off. The clock has three 12V power sources: one from the dome light circuit that is always on to keep the time, one from the cigarette lighter circuit that turns on the display when the key is turned, and one from the tail light circuit to dim the display when the lights are on.

 

[newsomew]

I checked the truck this morning after parking it late yesterday evening and the clock is still on and not enough juice in the battery to start. What can I do. I really don't need a clock so I suppose I could pull a fuse or something, but I don't really want to loose power to the cig. lighter, etc. Any suggestions?

 

[Cabrito]

Sounds to me like somebody modified it to stay on along with the Cig lighter. When the FJ62 key is turned off the lighter will not work and the clock is off. They probably wanted to be able to use the cig lighter when the vehicle is off. Maybe that is why your battery is being drained.

Your battery might need to be tested or replaced at this point because of the repeated discharges, but I would wait to replace it until you fix whatever is draining it.


I don't start my rig for two to three weeks at a time between trips and it always starts up. This is with the small LED for my alarm on the whole time. After three weeks it can be a little sluggish but not drained.

 

[haryv]

Do you have a digital multi meter? Put it on amps mode, then bridge the positive battery terminal to the dmm. Put the other lead on the battery cable. Check the current draw. Should be in the vacinity of 20 ma to 40 ma. anything larger then this, then you have excess current draw with engine off. Start pulling fuses and observe the reading on the display. If any fuse drops it down to the 20 ma region, then you found the circuit that is drawing the extra amount of current.

I once done this on a bmw once. Battery would be dead every two days. Found that the radio keep alive memory or support circuitry was drawing way to much current.