Charging issues

[normabramsonacid]

Hey Guys-
I'm new to repairing my vehicle and would appreciate any insight you all could add. I have a 2001 XLT 3.0 v6 4x4, and have been having electrical issues intermittently. I'll include everything that may be related.
- The turn signals have worked intermittently for 2+ years. A swift kick under the dash usually gets them working again.
- The dome light was smashed when I was loading things in the cab one day and I haven't bothered to repair it
- After taking my key out of the ignition the truck keeps dinging at me with the door open like i've left the key in the ignition.
- My battery drained down low enough that while driving my windshield wipers and radio worked intermittently, the engine was running rougher than usual, and the battery gauge and tachometer both dropped to zero, before the tach jumped back up to 1,000 ish.
- I was able to get to an auto parts store to swap the battery and ordered a multimeter to check some things.
- After being driven for a few days, then parked, my battery read 11.5v, and the engine still turned over. While running, I cranked it to 2500rpm and the engine was a hair over 12v. After running for 5 minutes or so and turning the engine off, when I tried starting it again, the battery was clicking and the engine wouldn't turn over.

I have a multimeter and a lot of free time. What's next?

 

[alwaysFlOoReD]

Alternator isn't charging. Get it tested to be sure.

 

[RonD]

Yes, alternator is not working but could be a fuse

KEY OFF testing
Set Volt meter to DC volts usually 20vDC is a selection, but any one higher than 12volts is fine
Test battery voltage, you need this number for the other tests
Say its 11.5v, remember it, under 12v is a drained battery, car battery should be 12.3-12.8v, 12.8v new, 12.3v after 5/6 years

Put black meter probe on the alternators metal case, thats the Ground connected to Battery Negative
Put Red probe on the B+ terminal on back of alternator, the stud and nut terminal
Should see Battery Voltage exactly, so 11.5v or whatever you saw connected directly to battery
If not then fusible link is bad

Now unplug the 3 wire connector on the back of alternator
Still using black probe on alternators case test Yellow wire, should see Battery Voltage exactly, if not fusible link is blown

Now test Green wire, should see 0volts
Turn key on, engine OFF
Retest green wire, should now see Battery Volts maybe .1-.2 less, if not then Fuse #11 in the cab fuse box is blown, 7.5amp, replace it
This green wire is the ON/OFF switch for alternator, also powers Battery Light in the Dash, Battery Light should always come on with Key On, then go off after startup

Look at the white wire, the jumper wire, should be plugged into signal port in alternator, just make sure it looks ok maybe unplug it and look for corrosion and plug it back in


If all 3 wires, B+, yellow, green, all test OK then truck wiring is GOOD
Replace alternator

After new alternator is install start engine
Battery should NOW read 14.3-14.9volts
Thats the alternator working
It may take 10-15minutes to recharge low battery but let engine run, or go for a drive
Then BEFORE shutting off the engine retest battery voltage, should now be 13.5-13.8volts, under 14volts, this is GOOD that's the voltage the system should run at when engine is on
Over 14volts for too long will "cook" a 12volt battery, its OK for fast recharge but not good long term

 

[normabramsonacid]

Wow. This is incredibly helpful. I'll give this a go tomorrow and report back when I get this figured out

 

[Curious Hound]

Just in case you don't believe those guys,

Your alternator isn't charging.

Do what @RonD said.

 

[normabramsonacid]

Good news! New alternator is in and working great. Thanks again. Just in time to not go anywhere

 

[Curious Hound]

Good job.

 

[Grumpaw]

Good news! New alternator is in and working great. Thanks again. Just in time to not go anywhere

Yeah, but now you can go nowhere in a truck that will get you there reliably.
Or is it, you can't go anywhere in your truck, even though it would now get you there.
Wow, these times are very confusing....
Grumpaw