Ongoing/ Intermitent Electrical Problem.

With the battery disconnected, measure ohms across the battery leads, looking for continuity through the vehicle's circuits. Pull one fuse, having noted its size and location on the distribution board, and note the change in resistance reading. Repeat until the ohm-meter shows ∞Ω. Whichever fuses had the greatest impact on the resistance reading indicate the circuits into which further investiagtion is needed. Use the vehicle wiring diagram from the Haynes Manual (usual disclaimer) plus local knowledge of any unrecorded aftermarket modifications until the fault is found and eliminated.

Oh, do take a note of the security code for things like immobilisers and in-vehicle entertainment systems before starting this activity, BTW. They will be needed to restore their functions after the testing is complete.

Frequently, it is a problem with the cables that connect to the battery. An open circuit looks like a dead battery, but a voltmeter will tell you otherwise.

The crimp of a connector on the end of the cable can sometimes look OK and hide a real problem. If it is easy to bend, the wire is nearly broken. It should be rather stiff.

I would also look at where the negative cable connects to the frame. Sometimes this cable is connected to the engine block which then needs a cable to the frame because the engine is sitting on rubber motor mounting blocks.

If grounding is achieved through the frame, is your frame in good shape - no broken welds? My favorite muffler shop has a mechanic that is good at locating problems like that. My point is that you may have to put it up on a rack to get a good look underneath for frame issues because the frame is a conductor throughout the car.

I have a dodge van that will occasionally drain the battery overnight. My problem is with the ignition switch, even though I put it in the off (lock) position, circuits can remain energized. My solution is to jiggle the key switch and ensure that he radio and heater fan can not be turned on.

I agree with Joe, probably an electrical connection somewhere, either on the battery or the frame...I like to use conductive grease on these connections to eliminate corrosion...

conductive grease link not an endorsement

I've used this method to detect drains on new cars.http://www.youtube.com/watch?v=B__DqK90IIc&feature=related

Go to TDR.com, 3rd generation diesels, you will find answers there, or somebody that knows what is going on.

As I recall, this is a common problem, and in the end is the result of something being left on that looks like it is off. On the 4th generation, 2010 and newer, its the high end radios that have a software problem that causes this.

Jim

Greetings.

I was told that (1) defective diode in your alternator could cause your problem.

I was talking with a technician at work and said that that my farm truck (1968 Chev hd 3/4 ton) was fine as long as I used it often but when it sat for awhile the battery went dead.

He told me that he had had a problem where there was one diode in his alternator that would slowly drain the battery.

I checked the cables with a clamp on ampmeter but couldn't find anything.

Its cold and wet outside. I just disconnect the battery and reconnect when I need it.

Nice warmer weather and I will pull out the alternator and take it in to have it tested or replaced.

I replaced it 24 years ago. Just don't last like they used to.

Hope this helps.

Have a Great day.

Oly