Charging System Problem - F'in Contour

Captain420 · Mar 26, 2012

If this is in the wrong section, by all means move it. Read the bold for the faster version.

Ok, over the last 48 hours I've had problems with the battery light coming on and flickering in my DD, which is a 98 Ford Contour with the Zetec (4 banger). Went to Advance Auto yesterday to have it tested and all the voltages came back ok, except the battery was on it's way out, which I knew anyway.

So, I went and replaced my battery and then the light turned off and stayed off until I got the Contour home. Then, this morning I start the Contour and low and behold the battery light came back on. So, I went to advance auto to have the battery and everything tested again. However during the tests the battery light turned off and everything read normal.

So we tested the Contour for a third time and bam, the light came back on during testing. So the charging system is charging the battery at 12.3 volts, so obviously it's something with the charging system.

My questions are, is the alternator something that dies a slow death? Or that quits rather quickly?

What are the odds its the belt tension and not the alternator itself? I ask this because above 3k rpm the charging system works and the light remains off. However, as soon as I idle for a while or drive under normal conditions (I never push the motor above 3.2k rpm in any city driving) it comes back on.

Also, my AC unit pulsates the RPM at a stop and by this I mean the car runs fine with the blower running and then when I have to come to a stop the RPMs will go from 750ish and they'll jump to 1000 rpm and then back down. I've read that this can be not enough tension on the belt. The AC doesn't even blow cold air, but I don't care about that problem yet.

Also, does anyone have or know of a way to test the belt tension?

Twista · Mar 26, 2012

I once had charging problems. Took my ALT to about 3513414 different auto stores (different store.. advance, auto, murray) and every single one of them PASSED the pos ALT. This went on for weeks till i got fed up and just brought a new ALT and all my problems went away.

Sometimes you cant figure out a charging problems without just throwing a part at something that passes the autostore test.

vermilion · Mar 26, 2012

check grounds. when in doubt change alt and battery.

Captain420 · Mar 26, 2012

Twista said:
I once had charging problems. Took my ALT to about 3513414 different auto stores (different store.. advance, auto, murray) and every single one of them PASSED the pos ALT. This went on for weeks till i got fed up and just brought a new ALT and all my problems went away.

Sometimes you cant figure out a charging problems without just throwing a part at something that passes the autostore test.

Well my charging system actually failed the Advance Auto test, when the battery light was on, which meant the charging system wasn't working properly. The Contour should be charging the alternator at 14.4 volts not 12.3 volts, so that's how I know that. The battery has been going bad for multiple months, which is why I bought the battery first. I'm not throwing any parts at it and I'm not sure exactly what the last sentence means but I am by NO means throwing parts at it, unless that's what you're suggesting the only other part I can try is alternator without trying a fuse or ground wire. Either way, I don't want to have to replace the alternator if I don't have to, but it's looking like that's what needs to happen.

CC'S95GT · Mar 26, 2012

Alternators, being electrical, sometimes don't act up till they get hot or vice versa.The voltage regulator in inside the alt. is dieing. That's why the light goes off above 3k rpm's. What is the voltage out above 3k?Do you have a multi meter or just going off the autozone test?The belt tensioner may be the culprit too but I doubt it in this case.Todays cars with all the electronics act wierd wothout a properly working alt and batt.Fix the charging issue and I bet the surging idle will go away.

Twista · Mar 26, 2012

Captain420 said:
Well my charging system actually failed the Advance Auto test, when the battery light was on, which meant the charging system wasn't working properly. The Contour should be charging the alternator at 14.4 volts not 12.3 volts, so that's how I know that. The battery has been going bad for multiple months, which is why I bought the battery first. I'm not throwing any parts at it and I'm not sure exactly what the last sentence means but I am by NO means throwing parts at it, unless that's what you're suggesting the only other part I can try is alternator without trying a fuse or ground wire. Either way, I don't want to have to replace the alternator if I don't have to, but it's looking like that's what needs to happen.

i meant just sucking it up and buying a new alternator and see if it works.

94 DropTop · Mar 28, 2012

I see a problem on some of the fords at work is the fusible link that goes between the battery and the alt. normally on the fuse block. A lot of times it won't be fully burnt up and just isn't letting the full amount of the voltage threw. Check that first.

ttocs · Mar 29, 2012

I would just guess the voltage regulator in the alt is taking a slow shit. Start the car up and then go and do some technical taps on the portion where the hrns plugs into the alt(the voltage regulator) and see if the voltage varies. Sometime the diodes in the bridge rectifier start to develope some loose connections and will make contact depending on temp/vibrations.