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Followup To
Question -
Roland,
Purchased car used @ 6 months ago. Ran great for 3-4 weeks. Started having problem w/ engine not turning over (get a clicking sound when you turn key). Got to point where repeated attempts car would not start. Replaced battery, fixed issue for @ 3 days then back to same. Took car to local shop and they said it was a bad battery! Replaced battery again, same deal and now we are at point that car won't turn over at all, just clicking when you turn key in ignition.
Answer -
Hi Julie,
I think what you have going on there is some electrical component/circuit which is connected to the battery even though the ignition switch is off is misbehaving and drawing more current than it is supposed to. There are a number of things that need power even though the car is shut down (radio stataion preset memory, body computer memory, emergency flasher circuit, powertrain/transmission module memory, etc.) but they take so little current that it will not discharge the battery unless you let the car sit for a couple of months without starting it. But this is happening to your car in a couple of days.
What you need to do is use a digital ohmmeter to measure the resistance between the two cables of the battery after you have removed them from the battery. Begin always by removing the clamp on the - post of the battery, then the + post. Reverse the order when replacing the cables on the battery posts, later.
Then see how many ohms reading you get between the two cable clamps. It will be a low number of ohms (like one to several ohms). Then go to the power distribution center which is a rectangular box behind the battery, next to the driver's side inner fender (directly behind the washer fluid filler). You will find a double row array of fuses numbering 10, two rows with 5 in each, and on the inboard side of the box 3 fuses (maybe one empty socket). Begin by removing one fuse at a time, note how much the resistance increases, write down the number of ohms, then replace the fuse. Do that for all 13 fuses and write me back telling me which fuse caused the biggest increase in the resistance reading. Then we will examine what items are fed by that fuse and go about checking each to find the one that is malfunctioning and drawing too much current, thus running down your battery.
Roland
Roland,
What is a digital Ohmmeter and where can I get one? The rest I understand and can follow thru on.
AnswerHi Julie,
It is an electronic test instrument that is used by tv, auto, computer, etc. hobbyists whose 'toys' incorporate electronic circuitry. The instrument will almost always read voltage (electric potential) and ohmage (resistance to the flow of electric current) and at an additional charge amperage (electric current). The digital aspect is that the presentation of the value of volts, ohms or amps via numbers on a readout screen rather than a moving needle presented against a meter scale. They can be bought for $10-20 because they are mass produced in China, etc. You could watch for a sale at Sears, Radio Shack, or any electronics parts store. A neighbor might have one you could borrow, or depending upon where you work a lab tech might have one. What you want to be sure is that whatever one you use it needs to have an ability to distinguish between small differences in small resistance values. So in order to tell the difference between 1.5 and 2.5 ohms you have to have a unit with several scales for different maximum ohms and one of those would need to be able to measure a maximum of 20 ohms with 3-places, e.g. 20.0 ohms maximum. Usually there are three digit displays so that a meter that only read 200 ohms max as its lowest range would be difficult to tell the difference between 1.5 and 2.5 because both resistances would mostlikely be seen as 002 ohms on the 200 scale, while on the 20 scale it would be 01.5 and 02.5 The meter comes with two wire probes, one red, one black. The black is plugged into a socket labelled "-" and the red into a socket labelled V or the greek symbol Omega, or a socket with both those labels and a dual-function switch to make the distinction between measuring either ohms or volts.
So see if you can find someone to lend it to you or watch the advertisements or look up in the yellow pages for electronics parts stores.
Roland
