I have a truck (in signature) that does not seem to be charging properly. My ammeter does not seem to be working. I first noticed it when my heater was on high and not blowing as much as it usually does. I checked my resistor pack, seeing as thats what usually the problem is. It was fine. So I just left it. That was yesterday morning.

This morning, same thing. So I decided to investigate a little further. I turned on my wipers. They were slow as well. So I left my truck running and go out with my volt meter. It tested at 10.9 volts. Hmmmm......I charged the battery. At the end of the day I went and tested the battery with the truck off. It was 12.5 volts. I started the truck.....12.1 volts.

I assume this vehicle has a external voltage regulator? Is it the small box (4" by 4") mounted on the passengers side fender near the solenoid? If so, I had a spare voltage regulator laying around that I knew worked so I swapped it and it gave the same readings.

So I hooked a booster cable from my negative post on my battery to my engine block and still same. I checked my belt to my alternator and it was a little loose so I tightened it. Same readings.

So can I assume that my alternator is shot? If so, what size alternator does this truck take? Will 60 amps be enough for a 5.0 L V8 without air conditioning. I don't run anything else major on this truck that will draw a lot of juice. I do have a 1000 COLD CRANKING AMP battery. (which is probably why my truck hasn't gone dead yet!)

Any suggestions, let me know!

-Matt

 

Your Alternator is probably going. Take it to Advance and let them test it for you, its free, couldn't hurt

 

But I live in Canada, eh?! I guess I can go to Canadian Tire!

-Matt

 

Matt, what Rpm was the egine at when you checked for voltage ?

The VR doesn't kick in until about 900 Rpm

 

I held the voltmeter on the battery when it was idling (at around 500 rpm) and it read 12,1 volts. I left it on the battery and my friend revved the engine (to at least 1300-1800 rpms) and it still read 12.1 volts. I checked this truck's voltage when idling about 3 weeks ago (after I had a battery installed) and it was around 14 volts.

-Matt

 

I vote it's the alternator.

 

Didn't think about there not being an Advance in Canada aye

 

Well, I swapped out an alternator I had laying around and I still had the same problem. I don't think the alternator is the problem unless the one I put in is shot too. I am going to Canadian Tire tomorrow with the alternator that was in the truck in the first place and get it load tested. If it tests ok, what should I look for next? Thanks guys!

-Matt

P.S. It is externally regulated.

P.P.S. 1/2 Ton FUn......it's EH?! not aye........

 

How about the fusible link on the starter relay, I think it is on a black/orange striped wire.......could have blown and caused the no charge problem....
Try checking the voltage at the alternator "BAT" terminal....if it is higher than the battery voltage with the truck running the alternator is working...so the problem is between the Alt "BAT" terminal and the starter relay battery + terminal.
Could also be wiring to the regulator, as in broken wire or corroded connector pins.......or even a bad igntion switch...as it sends a signal to the regulator to effectively turn it on.
If it isnt the alternator or regulator that pretty much leaves the wiring :-(

 

I was thinking about it being the fusible link. The same thing happened to my dad's 87 F250 6 months ago. How do I check if it is bad? I know that it goes from the alternator to the solenoid. When its at the solenoid, I believe it is a red wire. It also has a black rubber piece on it. Does it break inside there or just anywhere in the wire. I am going to go outside and see what I can find. Any other ideas? Let me know.

-Matt

 

Well, I went out and did some investigating. PROBLEM FIXED! There are 3 wires that go to a plug that goes into the external voltage regulator. They were fine but it seems that the plug harness was changed because further down there was some tape. I unwrapped the tape and the three wires were connected to three different coloured wires that went to the plug that went into regulator. This is fine except they were connected with butt connectors and taped. They was a lot of corrosion and when I unhooked the tape one of the wires unhooked! So I cut all three wires back a bit and hooked them back to the harness and soldered them. Then I put shrink wrap on it (that stuff is awesome!!!) and then wrapped electrical tape around all three wires. All seems good now. At first I had a readiing of 13 volts. A little lower than what I wanted. So, I revved the engine a bit and it went up to 13.7 volts. Once it idled back down it settled at about 13.5 volts. Then I turned on my headlights and put my heater at max. While idling it was 12.8 volts. With all this on I revved the engine and it said 13.4 volts. DO those numbers sound right? The truck has a 1000 cold cranking amp battery and I believe the alternator is only 60 amps. With the truck off and nothing on, I get 12.4 volts at the battery. Thanks for all your help guys. Any other comments, be sure to share.

-Matt

 

Those numbers look good.

 

OK. Thanks. I was pretty sure that was the problem. Thanks again everyone!

-Matt