Battery not charging; battery light on.

Hello I have a '97 contour v6. I am having problems with my battery not charging. I did a little troubleshooting and looks like I may have a drain in the electrical system.

With the car off, I disconnected the negative battery cable from the battery, and measured from the disconnected (-) cable to the negative terminal of the battery I am reading ~ 12.5 volts. This should read 0 volts - correct.

I have pulled every fuse, and it still reads 12.5 volts. Could someone please tell me if this is the problem. From Haynes repair guide book, it states that a trouble light should "NOT" come on. So if I am reading 12.5 volts (the trouble light would come ON) using a ohmmeter, it means I have a drain - correct. I don't have a trouble light available to try it.

What would cause the drain ? I am not able to get at the cables to the alternator to disconnect them (don't you love how the alternator is install on this car, can't do anything - until you pull the car apart - FORD idiots). Alternator is about 2 1/2 years old.

I checked the cables as best I can, grounds, and the mega fuse looks good too. With the car running only reading 12.5 volts, I know it should be ~ 14.4 volts.

Is the drain the reason the alternator is NOT charging ? I really don't think the alternator is bad and the belt is new. Not making any noises.

Any help would be greatly appreciated - I need to get my car working so I can find a job. If you can think of anything I could check..please let me know. I really don't have the money for a new alternator.

DRM

Innisfil, Ontario.

not sure why you would pull the negative terminal and then measure between the terminal and the battery post. Either way the battery should rear 12.5 volts across the battery, and in the electrical system, with the car off. this isn't a voltage drain, its the voltage of the battery. The battery appears to be good.

you need to test the voltage across the battery terminals with the engine running. make sure all cable are attached and tight. if you still get 12.5 volts or less then the alternator isn't charging, otherwise its should be ~14 volts. if not check the mega fuse. and if that is good then you need a new alternator.

Thanks for your replay, BrApple:

Well, my battery is now dead completely dead; there has to be a drain somewhere in the electrical system. I had the battery fully charged, and it was able to start the car. After letting the car sit for 2 days, the battery is totally dead. Would a bad alternator drain the battery if the car was just sitting there ? I really don't think so. I don't have the tools or know how to remove and test the alternator; or a gargage.

I have read some good info on checking for a drain, using a digital volt meter and will try that again later to find a source. I know that all the fuses in the panels are good; under the hood and in the car itself. I pulled every single one of them - all good.

Does anyone have a post or link on how to check, replace, remove the Mega fuse ? I know where it is located on my 1997 Ford Contour V6, but it is almost impossible to access. I know you have to remove the timing coil, but even then it is a pain in the ass to get at.

Any other info on checking the power cables to and from the alternator and battery would be helpful too.

Remember that just because your "battery" light is on does not mean its your battery. It means there is a problem in the charging system. How long did you drive your car with the battery light on? You may have just been running off your battery and your alternator was doing nothing. If your alternator goes out the car can no longer generate its own electricity. So it uses the battery instead. Once the battery is drained that is it. Also you can be reading 12V but not have amps to start the car. The battery's only purpose really is to start your car. Yes it keeps the memory on your clock and ECU as well. But once your car is running the alt takes over.

You CAN test the megafuse without removing anything (I have done it) with your multimeter set to Ohms. Also moving the coil pack out of the way really is pretty easy. You don't have to take it off the car to get back there. I only had to remove one spark plug wire to do it. I basically sat on my engine while removing the 4 bolts. Since you say you know where the Megafuse is, To test you have one test lead on one side and the other test lead on the other side with your multimeter set to Ohms. You should have little to no resistance. Coming out of the megafuse on both sides is the positive battery cable that goes to your alternator. There is also metal ends on both sides of the megafuse at the ends of the cable. you place the test leads on those. this does not require you to remove the megafuse.

I said that you can test the megafuse without moving the coil pack. It is a tight fit for your hands but it can be done. I stuck one test lead on and hoped it would stay after i let go then suck the other test lead on the other side. A helper would make it a little easier. If you remove the coil pack you would have better access though.

This is a post i found a few months ago.

Alternator

the "batt light" has nothing to do with the battery. it is actually a "charging system indicator light".


Replace the alternator, or POSSIBLY the megafuse (only thing that negates the megafuse is the off-and-on light. a megafuse would cause a steady light at all times, which you had at the END but not at the beginning.



1. Check the fuse, first (under the coilpack.. you'll see two metal posts sticking up.. measure resistance across them.. should be near 0)

2. Measure running voltage(alternator): check voltage across battery terminals while running.. should be 13.8-14.7 +- .3

3. Measure off-voltage(battery): turn off car, remove surface charge (interior and headlights on for 60 seconds)..
should be >=12.0
How-to for alternator replacement is under Duratec Maintenance FAQ


Ray

Click to expand...

http://www.contour.org/ubbthreads/s...allposts&Main=1095791&Search=true#Post1097673

First off, If you live next to an Advance Auto Parts(and can drive the car there) they will test your electrical system for free!

Next, an alternator with a blown diode(s) will cause a drain on the battery! so yes a bad alternator could drain a battery dead just sitting there.
Also a bad battery could appear to be good when fully charged but can slowley drain itself overtime. Only way to tell is to fully charge the battery and let it sit unconnected for a few days.

It sounds like its the alternator, and i would suggest putting in a ford dealer reman in it. If you buy from a parts store be prepaired to get it replaced again soon.

Thanks for all the info guys,

If the diode on the alternator is blown, and there is nothing else wrong (no shorts or drains, bad wire harness or mega fuse), is this the least expensive solution. Could I get a mechanic just to replace a blown diode on the alternator. OR will a gargage try to make me replace the alternator completely and charge me for it.

I have re-charged the battery, and it is holding a charge of ~13 volts for a few days now (not installed on the car). So I don't believe the battery is the problem. Bad weather here, I have not installed the battery to see if it will turn-over; start the engine. I understand that the battery light, is a an indicator of the charging system only - and I should be reading ~ 14.4v if it is working correctly with the car running.

I guess there is no way to checking the diode without removing the alternator completely (and paying for the removal and re-installation) OR will a electrical systems test reveal that ? I rather pay for a say cheap diode..than a complete alternator any day. What does the diode cost, like $ 3.00 ?

Thanks Again...

Honestly if you are going to have someone replace the diode i would suggest replacing the whole alt. How many miles are on your car?

I have a rusting 315,000 +/- kilometers on my car, the only car I have. Out of work because of the Economy...I just love my Life.

I am having the same troubles. I just installed a turbo and thought I messed something up. Lol. I am going to get my system checked at advanced auto today. I will see if they can test the mega fuse too or just the starter . Don't know how they do it but I will let you know.