Why is my battery always dead. It is less than a year old. alt is good. I checked the draw on the battery and got a reading of .39. Is that enough to drain a battery.

 

Yes, .39A (390mA) is enough to draw a battery down. I had a power draw of .12A (120mA) and it would pull my battery down over the course of a weekend. The maximum sleep current draw you should see would be in the 50mA range with ideal being around 35mA. By sleep, I mean when all of the modules go to their lowest power state. Most of the modules in the truck will remain active for a period of time after you turn the key OFF. After 5 minutes, they all should be at their lowest power state and you will get an accurate reading on the true current draw.

You need to figure out which circuit is causing the draw first, then work from there. I would leave your multimeter in series with the negative battery terminal and cable by disconnecting the negative terminal. Put the negative lead on the battery terminal and the positive lead on the cable end. Then remove all of the fuses. Put the fuses back in one at a time and watch the multimeter. If it spikes high, drops down after 30 seconds, then again after a minute, wait 5 minutes and record the reading. Remove that fuse and start again with a different one.

 

Well I guess now is a good point to ask, do you have any addons like cbs, scanner, extra lights, amps, sirens, extra horns anything along these lines? Also if you do are these wired into constant 12v or switched 12v? If you do have any of these its possible it is going bad and drawing too much current.

 

yes i have 4 switches that are lighted. when i disconnected them i got a reading of .07. Which is still kinda high. Would a radar detector draw power even if its off. Also were can i tap into a switched power source for the switches?

 

Well depends on the radar detector and where its connected to. You should be able to get the switched power behind the radio, at the onboard computer thing on the roof, which I think the wires arethere even if you dont have it. There should be some other locations around with switched power. Do you mean that your draw was .32A lower with the switched disconected.

 

i get a .39 when they are connected and a .07 when they are disconnected.