Every time the temperature gets down around 30, my truck (really hates the cold) decides that I don't need lights while I'm driving. She's great until she warms up, then I get a battery light, a "check charging system" message on the dash and every single light, my radio and amp shut off. I can still drive (as long as I can see.)

I was told this was because my battery was bad; my battery is two weeks old. This problem is the reason I got a new battery. My alternator was replaced last November.. I'm not sure how long they last but one year doesn't seem like that would be worth what I paid for it.

I DO have one !0 in sub under the seat, I'm not sure if that would be causing any problems since this only happens during freezing temperatures.

Oh, when I do a system check, it shows everything as okay.. Any ideas?

T.I.A.

 

The voltage regulator in the alt is most likely bad.. our truck's are very picky when it come's to Alt's .. did you install a cheap re-man ? You should have a 1 year warranty on it.

 

What brand alt? These trucks love OEM alts

 

Whoever told you to replace the battery should be ashamed if they did not test first. Almost every parts store has a battery tester on hand and many have newer versions that will perform a more sophisticated test.

You need a proper diagnosis before moving any further ahead. A simply multi meter can tell you a lot. Check voltage when you start it, check again when all the warnings happen. From there you can start tracing the problem back.

FWIW, a failing voltage regulator can ruin an otherwise good battery in short order.

 

The guy at oreillys tested the alternator and the battery, he said the battery tested bad. He also told me that I had to have a $300 battery but I'm not THAT stupid lol. I bought my alternator at Auto Zone, it looked exactly like the alternator I pulled off...

So I need to go to another parts house and get them to check it out before I do anything else?...
I mean I don't mind spending money on parts my girl needs, but if it ain't broke don't fix it lol.

 

I honestly do not remember the brand, I've drank *a lot* since I bought it lol.

 

Well you most likely did not buy a Motorcraft alternator at Autozone......

$260 for new after core and $202 for reman after core (both Motorcraft off Rockauto).

 

Duralast actually, I found my receipt.

 

Well thats most likely your problem. There are countless threads saying that anything other than Motorcraft alternators will give you fits. So much so that when I need a new one, it will get a Motorcraft.

 

For whatever the reason... Most box stores are selling alternators with crappy internal voltage regulators. As stated by several above... This generation is picky about OEM alternators.

The reason your battery likely tested bad was the alternator wasn't charging it and when it was tested, the batt prob had little to no amps left. Trickle charge it overnight before you put the new alt on so your alternator is not trying to charge a dead batt from the get go. I'd also recommend having it tested again after the charge to make sure the old alt didn't toast it.