86 Lincoln Towncar battery discharges overnite. Where to start trouble-shooting?

Question

thanks for all the answers.battery checked good. alternator good.found that rear window defroster was coming on randomly.removed fusible link from starter relay for time being.

Answer 1

Start by having the battery tested.Auto Zone provides this service for free.Is the battery light on your dash coming on and staying on after start?If so, it could be that the alternator has gone bad and stopped charging the battery.This too can be tested at Auto Zone, but you have to remove it from vehicle.If the alt.tests good.Then it can only be the Voltage Regulator.A good test for the V. R. is: Do your lights get brighter when accelerating the engine?If so, remove and replace V.R. If battery is good, and alt good, then replace the Voltage Regulator.

Answer 2

A broken battery cable will not make your battery discharge. First I would make sure you are shuting off all accessories in the car at night, because I have seen stereos hooked to constant power that needed shut off even when the ignition is off. If you can jump the battery, and it starts all day, and the car doesn't die on you all day, then I cant see it being the alternator. Usually when they go bad they will stop charging your battery, then run off the remaining juice in the battery, which wont get you to far, then the car will die. Make sure all doors are closed, including trunk and hood, because if open the lights on those will drain your battery also. Check all of the obvious. Have someone check the gravitys in your battery, because those are the power cells that store the energy in your battery, and when they go bad, they will lose charge when not in use, Also if you don't have a maintinence free battery, make sure to check the acid level inside, and if low fill with water until it fills right above the fins you will see inside. Dont fill all the way up, because when batterys charge, the acid expands and it will seep out the top of the battery. You can test the alternator yourself by getting a volt meter, putting the dial on 20v, which means that setting will test up to 20 volts. With your car off, a good battery should read in the high 12 volt range, if not charge untill it is, then start your car and put the pos and neg leads off your volt meter on the battery posts(when running), and if your alternator is working your meter should read from 13 to 15 volts. Thats more volts than the battery, but thats how the alternator charges it when you drive.

Answer 3

Get a Haynes Repair Manual at the local Auto Zone or auto parts store in your area. It will troubleshoot and show you how to fix your vehicle. Also on the Auto Zone site has a section for vehicle maintenance
http://www.autozone.com/servlet/UiBroker?UseCase=S001&UserAction=viewSimpleDiagInfo&Parameters=info



Priority Action Part Type Cause
1 Inspect Alternator Low or no voltage output from alternator.
2 Inspect Alternator Diode Conductivity in both directions or tests open.
3 Inspect Battery Insufficient battery voltage/amperage
4 Inspect Battery Cable Corroded, broken or poorly connected battery cable.
5 Inspect Battery Test Amps Low amperage readings can be caused by a faulty battery, alternator or other charging system component.
6 Inspect Alternator Brush Worn alternator brushes or weak spring tension.
7 Inspect Alternator Bearing Worn or damaged bearings

Take it to Auto Zone or where they do free battery check on it. Your battery may have a bad cell and not able to hold any juice. Then the usual make sure the battery posts and clamps are clean.

Anyway, buy the book and it gots all the info and more to get you running.

Answer 4

I presume the battery is otherwise good.

A good place to look is the automatic radio antenna. My M-B had a broken limit switch and the antenna motor was trying to pull the antenna down when it was already down. If you have a sensitive voltmeter, connect it across the battery terminals and watch it. If there is a regular drop in battery voltage every 10-15 seconds my money would be on the antenna.

Try to do your tests in as quiet a spot as possible. If an electric motor is running when it should not you can hear it if things are quiet.

Another use for the voltmeter is to watch it while pulling fuses one by one. When the offending circuit is broken, the voltage will increase slightly. This will eliminate most of the systems in the car from being faulty.

Answer 5

Walmart or anybody that sells car batteries will load test and charge your battery for you. if you live in a warm climate with no cold winters, a good battery will last 4+ years. you probably have a dead cell, there are generally 6 cells in a 12 volt dc battery, it will hold enough of a charge to go to the store for 30 minutes and start it again, but overnight it shits the bed. Check to make sure your positive and negative connections on the battery, are clean with no white powdery corrosion, this corrosion inhibits the ability of the connection, thus the battery cant charge from the cars' alternator, or give sufficient enough power for cranking the engine. Also you may have too much of a power drain, did you recently hook up a car alarm? or a big stereo that draws alot of amperage, if so the alternator may not be able to supply all of the power from all of your cars' power needs ie: spark of spark plugs, radio, fan blower, elec windows, headlights, tailights, under car lighting, and hence draws power from the battery during normal operation, when it shouldnt. maybe the alternator isnt putting out enough amps?

Answer 6

Try Auto Zone, or who ever and have them place an amp meter between the negative terminal of your battery and the cable and see what the no load (everything turned off) current draw of the car is. The "hot all the time" current draw should be less than an amp. Anything higher indicates a near short or leakage from the hot all the time circuit to ground and may not be in a fused location. That can be caused from cable chafing to a bad radio back-up circuit to any number of things.
If the "no load" current is OK, then you have a battery or charging circuit problem.

Answer 7

you have to take the positive terminal off the battery and then just touch it to the battery terminal and see if you get a spark and if you do you have something draining the battery, you are going to have to pull one fuse at a time out of the fusebox and then go back out to the battery and retouch it to the positive terminal and see if it still sparks, when you have that one fuse pulled and then it doesn't get that spark when you put the cable to the terminal you have found the problem circuit.

Answer 8

Check for a draw on battery,remove neg bat cable,connect test light between -bat cable and -bat post,with doors closed,ign off,hood light bulb removed, should be no light,if there is ,you have a draw,again,with doors closed,remove fuses one at a time,if light goes out,you have found source of draw,and can take steps to correct.Common are,glove box light,trunk & underhood lights staying on.Best bet,take it to a shop.Also,battery may just be bad.

Answer 9

in the beginning start up by making use of removeing ur neg battery cable until now u flow to mattress interior the mornig hook it back up if its ok meaning skill is being drawin from someplace on a ford the alt dioide could be a p-roblem if the batterys ok interior the am have ur alt examined sturdy success desire this facilitates

Answer 10

verify battery cables are ok then I would start at the ignition switch.