I'm gonna check that again monday. I tested it saturday and was getting like 11.7 off alternator,then it would get sporadic, then back to around the 11.7 again. That's when I took the alt back to store and had em bench test it. Now I wasn't in the best of moods and a little broke when changing the alt didn't solve my problem so I may have just not been thinking clearly. So I'm gonna attack it tomorrow with a fresh mind,and a fresh cup of coffee..lol

 

If you are only getting 11.7 your alternator is not working.

 

That's what I keep thinking, but it bench tested @ 14.5? That's not what its doing on the truck. I replaced plug to voltage regulator to no avail,but battery light on the dash is brighter now? Then I got called into work so I haven't done any further testing

 

Instead of dropping parts in the truck you should invest couple of buck in the tester above and troubleshoot. Beside bad plug you might have bad ignition relay or burned out fuse.

 

That will not help to determine if the alternator is charging or not, it only will show if voltage is prewent, not how much.

 

We have confirmation that the alternator is good. Right now we need to check if it is getting activation power. That tester will tell that in about 5 seconds. Way shorter than type forum reply

 

it was bench tested at the parts store, that is no guarantee that it is good.

he said it is putting out 11.7 volts, not sure where he is getting that from, but if it is off the back of the alternator and that is all he is getting, it sounds like a bad alternator to me.

with a voltmeter (which he already has) and a little bit of troubleshooting skills, it isn't hard to figure out what the problem is.

 

I said “I believe” and I still do. You got lucky, twice, first time was when you removed the terminal and the battery did not explode, a never ever with a battery is never ever remove the connection from a charging source and the battery anywhere near the battery, only two things need to occur to cause a battery to explode and that’s a hydrogen gas concentration above 4.1% and a spark, and a spark will occur when you remove a connection under load. I learned this a long time ago the hard way. The second time was when you removed this wire it left the alternator self excited.
Neither removing the battery lead or checking battery voltage at the battery points to any specific faulty component, it only tells you the system is not working and the light did that for you, and trouble shooting by replacing components is costly.
If you want help trouble shooting this I have no issue helping, if not, good luck.

 

Just wait 'til you send a voltage spike the the ECM by doing this, you'll never do it again.

 

You are right that alternators like to play dirty tricks and can pass the bench test and have intermittent problem on the truck. Had one of those on my own.
But in this case problem is permanent and should be easier to troubleshoot. Alternator in order to work needs to have some battery power. If there is no power coming to it -there is no power going out.
So checking the power supply to alternator would be one of the first steps in troubleshooting.
You don't take the engine apart before you make sure the fuses are OK

 

I didn't post on here to debate whether or not to take the battery cable off a vehicle running is good or bad. Taking off didnt cause my problem,and leaving it on hasn't cured my problem,so that subject to me is niether here nor there. I posted on here to see if any one might know why my alternator bench tests good,but on my truck,not so much. I have physically checked all the fuses i could find and they are all good. like i said earlier,i havent had time yet to go around with my tester checking everything. The plug took 5min. to install and cost 10 bucks. Figured with my alotted time that would be a good place to start and what could it hurt

 

It might be a good idea to check and clean all ground connections between the engine and frame. Check and clean both ends. Sometimes a flakey ground connection can play havoc with these trucks. Not saying that's it...... but I know first hand that they need to be clean and tight just like battery terminal connections. It's free, no parts required, and it's also a good time to look for chaffed or worn wires through out the electrical system.

 

So i tested the regulator plug. Got constant 12v and switched. The excite wire is the one running from regulator plug to the the alternator right? is that tested in ohms or volts? tested in volts i got like.08 with truck running,but it would drop off from time to time

 

ohhhh the alternator drama continues.... see dennis this is why i dont help with alt problems anymore... same thing happened last time a "not charging" fault poped up on here. I think the players changed thow Ahhhhh live and learn I guess

 

I’ll try anything once so here goes. With your truck not running remove the negative battery terminal and follow the steps below. As I tell you to remove fuses do not put them back in until you finish or we may get good reading back thru some thing else and for that matter when I say to skip ahead read the next step and remove the fuse
1. Set your meter to ohms and test, (touch the two leads together) this will be “near” the reading we will be looking for.
2. Disconnect the 3 wires on the alternator
3. Measure between the positive battery lead and the yel/wht at the alt. (big wire with the ring connector) you should have the reading we got in step one, if not go to step 4, if you did skip to step 7
4. Find and remove your 175a mega fuse and test with your meter. If it’s good go to step 5 if not you know what to do
5. Measure between the yel/wht on the alt and where the mf plugs in. If you can’t see wire colors try both places where it plugs in. if your reading is good go to step 6 if not that wire is bad.
6. Measure between the other side of the mf to the blk/org on the starter motor relay. One wire from the positive side of the battery feeds to the starter motor the other to the starter motor relay. If you got to this step a connection is bad is this wire, when you check crimped stud connections check on the stud then the connector then skin a tiny of the insulation back to get at the copper and test there
7. If you skipped to here measure between the mf where you got your good reading in step 4 and the org/lt blu on the double wire connector at the alt, you should have the reading we got in step one, if not go to step 8, if you did skip to step 10
8. Find and remove the 20a inline mini fuse and test with your meter. If it’s good go to step 9 if not you know what to do
9. Measure between org/lt blu on the double wire connector at the alt to the plug in on the mini then the other side of the mini to the mf where you did in step 7, check the connection of the connectors the way you did in step 6
10. If you skipped to here find and remove the 10a fuse 19 in the junction box fuse/relay panel and test it with your meter If it’s good go to step 11 if not you know what to do
11. Measure between the lt grn/red on the double wire connector at the alt and fuse plug at fuse 19, this is measuring thru the instrument panel charge indicator so I am not sure what kind of reading you will get here but try it anyway and let us know what kind of reading you get
12. From fuse 19 it goes to your ignition switch and I can’t help with that from here