Does anyone know the procedure for checking for a parasitic draw in a 1992 Dodge Dynasty?

Question

THE BATTERY IN THIS VEHICLE WENT DEAD LAST WEEK. I HAD THE BATTERY RE-CHARGED AND TESTED, THE BATTERY IS O.K. IT WAS BOUGHT NEW 2 MONTHS AGO. THE ALTERNATOR WAS ALSO CHECKED, AND IT WAS O.K. ALSO. I JUST NEED TO KNOW HOW TO CHECK AND SEE IF THERE'S A DRAW ON THE BATTERY. ANY HELP WOULD BE APPRECIATED!!!!

Answer 1

You disconnect one battery terminal and install a digital ohm meter, set to the amp scale, in between the battery and the cable that you disconnected.MAKE SURE that nothing in the vehicle is turned on,keep the doors closed during this test.Your meter will read the draw on the battery and should not exceed about 35 milli-amps on that vehicle. If the draw is higher than that, you need to determine what it's from.Tronary mentioned used a volt meter-that is incorrect. You must use the meter on the milli-amp scale.if you set the meter to measure voltage,it will not tell you the draw as there is always a small voltage through the cable.

Answer 2

I would suspect it actually is the alternator, specifically a diode.This specific test can be done by a shop you trust.

Answering your question:.You will need a volt meter.I assume your battery terminals are clean. Make sure the battery is fully charged. Try this:


Check all possible draw sources. Is there an aftermarket stereo, amp, car alarm etc. wired "hot" for constant draw? (I.E.;Does it work without the key in the ignition turned to ACC or start position?) With that checked, and you are sure there are no external "aftermarket" draws:

Take the key out of the ignition.

Make sure everything is turned off regardless ( circulation system fan, dome lights, glove box light, etc).Pull out the bulb, if your car has a light under the hood.

Turn on the Volt meter and set it to the "AMP" setting. Simply clamp the cables to the respective posts on the battery (Positive to positive, negative to negative) and check the display. Anything more than 4.0 amps would indicate a severe draw.

Now DISCONNECT the voltmeter from the cars' battery.

Set the volt meter dial to the" voltage" setting (Should be a "V" with a symbol next to it).

Disconnect the NEGATIVE terminal from the cars battery.

Clamp either one of the VOLT METERS' two cables to the disconnected NEGATIVE battery cables metal surface. (RED or BLACK, in this case it doesn't matter, you wont cause an arc).

Hold or clamp the remaining cable of the VOLT METER to the NEGATIVE exposed battery post you just disconnected.

Look at the volt meters indicator. Your car has a 12 volt system. So anything under 12.0 is insufficient and indicates a draw.

Most cars have somewhat of a draw always. The radio clock is one example., factory or aftermarket alarms are another etc.

Going further. To at least isolate a draw, leave the volt meter clamped as previously indicated during the VOLTAGE check. Start carefully pulling out fuses from your main fuse box, ONE AT A TIME.If the volt meters' indicator go's to zero. You know roughly what system is producing the draw.

Long post and I had a little time. Hope this helps. Good luck.

Answer 3

Was the alt. checked on the car ? With alt. installed you need to idle the engine and connect a voltmeter across the battery terminals. Should read approx 14.5 volts. If it does not you need to check the alt. fuse. If fuse ok then you have a wire disconnect between alt. and bat. Whoever checked the alt. and batt. should have done this. If you wish to check for parasitic draw, make sure everything is off, including ignition. Disconnect the NEGATIVE batt. terminal. Connect a volt meter from the negative terminal (wire) that you removed to the positive batt. post You may get a very small indication if you have a clock.