And another Alternator/charging issue - could use some help/input

[Mac99Snake]

Last week, I hopped in the car and started her up. I noticed that she cranked a bit slow, but then fired off. I figured it might be my battery as it was 8 years old. I put the top down, secured the tonneau cover and hopped back in and hit the gas to back up.....she sputtered and died. I turned the key and click-click-click-click. Ok the battery is drained, the top is down, the car is not running and I'm late for work. I grabbed a quick charger and was able to get enough juice to put the top up and close the windows. I left it on trickle charge and took the BMW to work. When I got home that evening, there was enough power to start her and move in to the garage. Diagnosis time = come to SVTP and start searching. I also looked through the shop manual for Ford's solution.

So, I decided to go at it from two directions, have the alternator rebuilt and pick up a new battery. As most have read, removing it was painful, but eventually it came loose and I took it to a local guy to rebuild. I also ordered a new Optima from Amazon.

Fast forward a week. I picked up the alternator and installed it along with the new battery. With the engine running, I check the volts at the terminals.... 12.18V hmmm...not working. I read through the diagnosis section in the shop manual and it lead to a bad voltage regulator...crap, I guess it has to come out again. However, back under the car, while removing the alternator plug, one of the wires came loose...aha I think. So, after some scrambling, I find a replacement pigtail at my local dealer. I replaced the plug, which from what I could see only used two of the three ports available. So I soldered the new pigtail on and put it back together.

Key in ignition, battery light comes on...yes
Key to run, battery light is on ....yes
Start car and battery light stays on .....NO!

I check the volts and its putting 14.2V to the battery.

Back to that shop manual....diagnosis says to replace the alternator.....crap.

I had an extra alternator that I had removed two years ago replaced by the Ford Motorsport version. Lets try this one... more cussing ensued however I did get it back together again.

Key in ignition, battery light comes on...yes
Key to run, battery light is on ....yes
Start car and battery light stays on .....NO!

I check the volts again and now its 14.5V to the battery.

So I'm at a loss....the battery is charging, but the battery light is not going out after the engine starts.

Any ideas?

Thanks

Mac99Snake

 

[Mystic03]

look for a break or shot to ground on the signal wire for the light...my 95 had that same issue right under the distrubituon box just pull the loom and look for breaks/short

 

[Snake Plissken]

look for a break or shot to ground on the signal wire for the light...my 95 had that same issue right under the distrubituon box just pull the loom and look for breaks/short

This makes since...

I replaced my original alt. at about 14,000 miles and it's at 18,900 now. Late last summer the light started going on and off randomly. Checked with volt meter, looked over the alt. and plug everything was cool. I do remember that when the alt. dumped on me the light never came on. Loose wire maybe. Well, at least this gives me something to check. I was running out of ideas.

Thank you sir...
.

 

[Mystic03]

no problem sounds just like what was happening to my DD light would stay on with the car off poked around and found it either grounded or broken i forgot but nonethe less that is probable your issue

This makes since...

I replaced my original alt. at about 14,000 miles and it's at 18,900 now. Late last summer the light started going on and off randomly. Checked with volt meter, looked over the alt. and plug everything was cool. I do remember that when the alt. dumped on me the light never came on. Loose wire maybe. Well, at least this gives me something to check. I was running out of ideas.

Thank you sir...
.

 

[Mac99Snake]

Problem solved....I chased wires with a multimeter for a while with no luck. On a whim, I rechecked the alternator fuse in the engine bay fuse box....yep, on close inspection it was blown. I slid a new 20A fuse in and she's all good again. I guess when the voltage regulator went bad on the alternator, it blew the fuse. I checked it first, but missed the little fried section. (I hate getting old eyes..)


Mac99Snake (its time for some new glasses)

 

[Mystic03]

glad to see you solved it! good find!