Charging issue

xtremeskier97

Original poster
Member
Feb 11, 2012
28
We just got back from a long trip with the Trailblazer. We drove from Shreveport, LA to Columbia, SC and back a week ago. Since we have been back, we have noticed that the truck had been getting harder and harder to start. When turning the engine over, it would get slower and slower, until eventually one morning, it wouldnt start. We put the jumper on the battery and it started up. Throughout the day it was hard to start, but it did. I put a trickle charge on it overnight and in the morning, cranked right up.

Well, I took a trip to Dallas yesterday (3-4 hours away) and did a bunch of running around there. I noticed that the truck was getting harder and harder to start, so at my last stop I just left the truck running. After driving to that stop, doing what I had to do there, and then driving home, the truck had been running for about 4.5 hours. I pulled up in the driveway when I got home last night and shut the truck off. I immediately tried to turn it back on, and all it did was click really fast and the dash lights blinked right along with the clicking.

I put the trickle charge on it over night, and it cranked right up in the morning. This is when I noticed that I had a fuel leak at the pressure regulator, so while I had the truck down doing that job, I figured I'd tackle the charging issue.

I took both the battery and the alternator to Autozone for them to test. They tested the alternator as good, but their battery tester was down. So I went down the road to Advance Auto and they tested the battery as good, but their alternator tester was down. So, I went to Oreilly, and they tested BOTH as good.

One guy at Oreilly said their may be a fuse that blew that is not allowing the alternator to charge the battery.

I'm about to go outside in the 100+ degree heat and check all the fuses, but wanted to post this beforehand to get some feedback.

Any and all help would be GREATY appreciated. I have to get this fixed. BTW, removing the alternator....PITA! Thanks GM! :mad:
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
What does the gauge in the dash read?
Was a load test done? Or just a voltage check?
Are all the connections tight?
When my alternator went out it was squealing and the voltage gauge was reading low.
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
The right side of the voltage gauge needle has been a hair to the left of the 14. I'm pretty sure the left side of the needle used to touch the 14.

The guy at Oreilly that tested the alternator is the one that mentioned about the fuse. He said that if that fuse is blown the gauge would read in the 13s.

I dont know if a load test was done or not. I sat there and watched both Autozone and Oreilly test the alternator. They both did it the same way. Hooked all the wires up and turned it on. I know it tested 3 things, because it had 3 lights in the top right corner that said testing as it moved to the next test. The result was "PASS".

BTW, they tested both of these on their bench. They were not in the Trailblazer at the time.
 

McGMT

Member
Jun 17, 2012
621
xtremeskier97 said:
The right side of the voltage gauge needle has been a hair to the left of the 14. I'm pretty sure the left side of the needle used to touch the 14.

The guy at Oreilly that tested the alternator is the one that mentioned about the fuse. He said that if that fuse is blown the gauge would read in the 13s.

I dont know if a load test was done or not. I sat there and watched both Autozone and Oreilly test the alternator. They both did it the same way. Hooked all the wires up and turned it on. I know it tested 3 things, because it had 3 lights in the top right corner that said testing as it moved to the next test. The result was "PASS".

BTW, they tested both of these on their bench. They were not in the Trailblazer at the time.

If the alt. wasn't charging at all it would show below 12 while running,,, When charging it will generate around 14 volt... Are your terminals clean? I would check your terminals real good make sure the wires are firmly and neatly attached at the terminal and that they are clean and free of oxidation...
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
All terminals were clean and well attached. No corrosion at all.

I just pulled every single fuse under the hood. All good.

Bout to check all rear fuses.

Thanks!

OH, and when I got home last night I got my volt meter out before turning off the engine and tested across the battery. It was 13.something. Turned off and it was 12.something (cant remember exact)
 

McGMT

Member
Jun 17, 2012
621
xtremeskier97 said:
All terminals were clean and well attached. No corrosion at all.

I just pulled every single fuse under the hood. All good.

Bout to check all rear fuses.

Thanks!

OH, and when I got home last night I got my volt meter out before turning off the engine and tested across the battery. It was 13.something. Turned off and it was 12.something (cant remember exact)

When you checked the terms, did u check where the wires go into the terms? That's what I meant to check just not sure by your verbage if you mean that is ok also... One thing too is to check all your under hood grounds and make sure they aren't too boogered up.. But in all reality if everything is attached and clean you might just have a bad battery with a cell gone wrong... Sometimes even a junk battery will test good but not charge off the alternator.
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28

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Vicompc

Member
Dec 5, 2011
109
Just had a similar problem with mine, the battery just died. After putting in a new battery the volt meter would fluctuate and the lights would flicker (both interior and exterior). I replaced the battery again thinking it was bad and had the altenator tested (it showed to be good). It turns out it was the voltage regulator in the altenator was sporadically going out which was causing the drain on the battery and the light issue. I replaced the altenator and everything is working correctly now.
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
Vicompc said:
Just had a similar problem with mine, the battery just died. After putting in a new battery the volt meter would fluctuate and the lights would flicker (both interior and exterior). I replaced the battery again thinking it was bad and had the altenator tested (it showed to be good). It turns out it was the voltage regulator in the altenator was sporadically going out which was causing the drain on the battery and the light issue. I replaced the altenator and everything is working correctly now.

This is what I was leaning towards too :sadcry: One of the guys at Autozone said that an alternator could test good every time you test it but still be bad.
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
The only cable I cannot seem to get to is the positive to the starter. Could the starter be causing this?
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
I was able to get to the starter wire. Looks good. Made sure it was tight also.

So, reluctantly, I put everything back together making sure all had nice clean, tight connections.

The following are the readings I took after doing so:

12.71-12.72 = Everything hooked back up with nothing on.

14.24-14.25 = Truck running, nothing on.

13.71-13.72 = Everything on/running (A/C front & rear, high beams, wipers front & rear, radio, hazard lights) 1ST READING

13.62-13.69 = Everything on/running (A/C front & rear, high beams, wipers front & rear, radio, hazard lights) 2ND READING


Thoughts? I'm so lost...
 

CaptainXL

Member
Dec 4, 2011
2,445
xtremeskier97 said:
I was able to get to the starter wire. Looks good. Made sure it was tight also.

So, reluctantly, I put everything back together making sure all had nice clean, tight connections.

The following are the readings I took after doing so:

12.71-12.72 = Everything hooked back up with nothing on.

14.24-14.25 = Truck running, nothing on.

13.71-13.72 = Everything on/running (A/C front & rear, high beams, wipers front & rear, radio, hazard lights) 1ST READING

13.62-13.69 = Everything on/running (A/C front & rear, high beams, wipers front & rear, radio, hazard lights) 2ND READING


Thoughts? I'm so lost...


Those readings look good. How many miles on the truck? If your up there then I would start suspecting the alternator. Also I would suspect the battery if it's more than 5 years old. Let us know how old both of those are. You can then pretty much make an educated guess. As has been discussed voltage regulators sometimes don't go out with a bang. If the rectifier lost a diode you could be pumping AC into your battery. Not good.
 

xtremeskier97

Original poster
Member
Feb 11, 2012
28
Both were in the truck when I bought it almost a year ago. There was 107k miles on the truck when we got it and it has just under 126k on it now. The battery is a Autocraft Gold battery from AdvanceAuto. It has a small green sticker on the corner with the date 09/09, so it's about 3 years old. These batteries have a 3 year replacement warranty on them.

The alternator, I have no idea. I'm still leaning towards it being the culprit, I just dont want to spend $150 on something I may not need.
 

McGMT

Member
Jun 17, 2012
621
xtremeskier97 said:
Both were in the truck when I bought it almost a year ago. There was 107k miles on the truck when we got it and it has just under 126k on it now. The battery is a Autocraft Gold battery from AdvanceAuto. It has a small green sticker on the corner with the date 09/09, so it's about 3 years old. These batteries have a 3 year replacement warranty on them.

The alternator, I have no idea. I'm still leaning towards it being the culprit, I just dont want to spend $150 on something I may not need.

Im gonna put one vote towards a wonky alt....
 

CaptainXL

Member
Dec 4, 2011
2,445
xtremeskier97 said:
Both were in the truck when I bought it almost a year ago. There was 107k miles on the truck when we got it and it has just under 126k on it now. The battery is a Autocraft Gold battery from AdvanceAuto. It has a small green sticker on the corner with the date 09/09, so it's about 3 years old. These batteries have a 3 year replacement warranty on them.

The alternator, I have no idea. I'm still leaning towards it being the culprit, I just dont want to spend $150 on something I may not need.

Could be sticking brushes in the alternator. I would first take it too a car wash and pressure wash the alternator to wash away any lingering carbon or dirt that might be keeping the brushes from contacting the commutator. Use water only no soap.
 

McGMT

Member
Jun 17, 2012
621
CaptainXL said:
Could be sticking brushes in the alternator. I would first take it too a car wash and pressure wash the alternator to wash away any lingering carbon or dirt that might be keeping the brushes from contacting the commutator.

I don't know how electrically inclined you are but I usually just fix broken alternators instead of replacing. And in this case I would split the case and give it a good internal scrub and replace or deglaze brushes as necessary.
 

tom1999d

Member
Apr 24, 2012
32
Try this. Remove the belt and spin the alternator pulley by hand in both directions. This could help clear and reseat the brushes (carbon sticks that touch the rotor of the alternator as it spins). Also remove, clean and retighten the battery connectors.

If you choose to replace your alternator I have a DIY with photos. I posted on Trailvoy and will post it here this weekend.
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
McGmt-
Are the new style alternators rebuildable? I remember in the mid 90's (for GM) there were some that were just replaced. There was something with the way the stator was hooked up that prevented splitting the cases.
As for the alternator problem-take off the NEGATIVE battery cable and put a 12v test light, one side to the battery and the other to the cable. It should light for a few seconds and then go out. If it lights at all after about a minute, you have a parasitic drain. If you use a voltmeter, the normal drain is something like 500 mili amps.
When doing this test, key off. Don't forget if you open a door, you have to wait for the interior lights to re-set.
If you have a drain, pull each fuse until the light goes out. Then you have to find what on that circuit is causing the drain.
Just for jollies, start with the seat belt switch (disconnect it under the seat). I've done several of them, maybe you'll get lucky.
 

McGMT

Member
Jun 17, 2012
621
NJTB said:
McGmt-
Are the new style alternators rebuildable? I remember in the mid 90's (for GM) there were some that were just replaced. There was something with the way the stator was hooked up that prevented splitting the cases.
As for the alternator problem-take off the NEGATIVE battery cable and put a 12v test light, one side to the battery and the other to the cable. It should light for a few seconds and then go out. If it lights at all after about a minute, you have a parasitic drain. If you use a voltmeter, the normal drain is something like 500 mili amps.
When doing this test, key off. Don't forget if you open a door, you have to wait for the interior lights to re-set.
If you have a drain, pull each fuse until the light goes out. Then you have to find what on that circuit is causing the drain.
Just for jollies, start with the seat belt switch (disconnect it under the seat). I've done several of them, maybe you'll get lucky.

I do believe they are... Now finding a rebuild kit for it is another story but I do believe that these "normal" one input wire ones are splittable and you could at the least clean them up. I had one not long ago that the internal plastic fan shattered and took out one of the leads on the windings. Soldered the F outta it but it just wouldn't hold.
 

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