02maxima

the battery drained down to nill and i cannot jump the car even with a charger on it. i have checked all the fuses. and had the battery checked it is good. i felt the relays but none were warm. any suggestions?

92_SR20

Have you done anything to the car recently?

carowmoto

So the car won't start at all or theres a draw that keeps killing the battery? And did you make sure the Alt. is chatging the battery while the vehicle is running?

02maxima

Alt works and battery is good i have been trouble shooting by isolating the cicuits with a multimeter. whatever is drawing power has killed my battery charger as well. I havent done anything to the car in over 2 years. i am about to check the alt solenoid i see that it works as a voltage regulator to some extent. and where is the hood light fuse?

92_SR20

Just poke around and check for any exposed wire / ungrounded wires.

Fabrik8

If you've drained the battery down that much, you've permanently damaged it. Disconnect the battery and check resistance between the two battery cables. I bet you'll find some fairly low value, so then you'll have to find out what is causing that.

You can isolate a lot of circuits by removing fuses or fuseable links (the bigger main fuses) while you're troubleshooting. That should isolate pretty much all of the accessory and power circuits, so if you still have a very low resistance short than the list of suspects gets really small really fast.

carowmoto

I usually use a parasitic draw test. Put your DVOM leads between the neg. battery terminal and the neg. terminal clamp and measure the Amp. draw. .015 to .022 of an Amp. would be acceptable. The problem is is that the test needs to be set to where you don't cause an inadvertant draw. So "trick" door switches into thinking they are closed but you can still access fuse panels.

My money is on an aftermatket CD player staying powered up or maybe electric seats causing a problem. I've seen seat covers pull on the switches and kill a batt. Nissan electric seats have power all the time along with the CD players.

Sorry I tend to rant...

Fabrik8

You can do the parasitic draw test, but you better not do it before you check resistance. If the resistance in low enough, the current will be high enough that you'll just blow the fuse inside the multimeter, and then you'll have to spend a bunch of time finding some obscure fuse type (my multimeters never seem to have common types of fuses inside).

By Ohm's Law (V = I x R), voltage equals current times resistance. So if you have a 12V system, and your multimeter can handle 10 or 20A of current, you better have a couple of ohms (minimum) before you even think about trying to measure current. This assumes that you've already isolated most/all of the branch circuits, because you can't really tell anything about the current draw of an electronic device (like an ECU) while it isn't powered.

If something is wrong enough that the car can't be jumpstarted, it's not going to be a parasitic power consumption problem, it's going to be a major short or a bad connection.

carowmoto

Hmmm... Ok. I see where we're going with this, I think... But, the OP isn't giving a whole lot to go on. On a side note tho... Fabrik8 what are you looking for when you check for resistance between the Pos. and Neg. batt. clamps?

Fabrik8

I'm looking for resistance, is this a trick question?


The amount of resistance will vary from car to car, but with the fuses pulled the resistance should be pretty high because pretty much all the electrical loads should be not connected to the battery cables at that point, and anything still connected will probably be isolated by a relay that isn't switched on.

Remember, you're checking resistance with the battery cables disconnected from the battery.


I'm really starting to think that this isn't an electrical short but rather a ground or power connection problem. The battery might not be charging, so the battery would be getting drained but not getting charged. The connection problem could very easily affect jump starting too, so this could very easily be something completely different than it actually looks like. Very hard to tell without a lot more information, and very hard to tell over the internet no matter what.