Driving my 96 F150 with 4.9 I6 the other day I noticed that my voltmeter read below NORMAL. Later that day it died.
I replaced the battery and the corrided connector.
My meter still is reading below normal. Later the next day for 5 minutes the meter read between the "O" and "M" in normal. I was relieved. Until the next time I started it and it was back down below normal. I want to fix it before I have to put in another battery.
Where would be good place to start looking? Going to replace the ground wire that connects to the wall today to see if it makes a differance.
Thanks for any thoughts.

 

Brent:

Start off cleaning ALL of the terminal connections on ALL of the MAIN BATTERY CABLES (all 3 cables) including the one on the frame that the NEGATIVE CABLE attaches to before going off to the starter.

If any of the ends or the center of the negative cable have corrosion or look suspect, REPLACE IT with TWO CABLES! One goes from the battery to the frame and the other goes from the frame to the starter housing. The above goes for the POSITIVE CABLES ALSO!

Clean all the small frame to body grounds with a wire brush until shiny.

Now that you have nice clean connection to the battery, crank it up and check the voltage with a Multi-meter AT THE BATTERY!!! At 1500 rpm it shouldbe between 14.3-14.8vdc. Once you verify that look at teh volt meter in the truck.

If the voltage running IS NOT up to par (say 12.5 to 13.8) then the alternator is at fault and should be troubleshooted and repaired/replaced.

Break out your haynes manual and go thru the troubleshooting for the electrical charging system.

Larry

 

Larry,
I have been all over the Haynes Manual today. I have never replaced the battery cables and live a few miles from the ocean. With that being said, there are two cables coming of the positive post, one to the starter and the other to, well i'm not sure where it's going, it looks like down along the said of the engine.
Would the cables make for more of a slugish performance? There is a little corrosion on them. Just did a tune up (without cables because I can't tell where the other "+" is going).
Not looking foward to replacing the alternator. The belt is not in bad shape at all. I think i'm going to see if advance auto can run a check for me to isolate the problem more tomorrow.
thanks for your advice.

 

I forgot your's is a 96 when I wrote the above about the postive cable. If the only thing corroded on the Positive cable is the end, clean it up and keep going! The positive cable is a DEALER ONLY ITEM! $$$$$$$$$$$$$$$$!!!!!!!!

The only thing Advance Auto will be able to check is whether your battery is ok and whether your alternator is good/bad. The better check on the alternator is the bench test they have. It eliminates all other possibly poor performing sections of the system.

On 93 and up Ford changed the Starter to a "Reduction Gear" starter with a solenoid on top. Kinda like a GM. BUT! They kept the Solenoid on the sidewall next to the battery. Here's the fun part!

Coming off the Positive Lead for the battery: LARGE CABLE goes directly to the 1st large lug on the starter Solenoid (top). This puts voltage to the starter thru the Solenoid. SMALL CABLE goes to the sidewall mounted solenoid (has that big molded cable assy with two LARGE lugs attached to it). The small cable is the one on the back side of the solenoid.

The wall mount solenoid only supplies power to the solenoid on the starter!!!

Now as for the Negative cable. They DID NOT CHANGE anything on it from at least the mid 80's. It still has a section of the sheathing removed and a compression clip molded around the bare wire and bolted this to the frame. CORROSION CITY! With you living in Va. Bch. (I live 10 miles south of Baltimore) I'm surprised it hasn't occured sooner. The corrosion hits this section and causes many problems with the charging and starting systems.

What I do with the Negative cable is get a I think 36"(with battery Lug) and a 60" (with plain ends, just the flat end so a screw can fit thru the hole, both ends.). Make them long enough to get from the battery to the frame and from the frame to the starter housing bolt. Clean to bright metal the starter housing, the frame at the hole and the battery post.

1.) Cut the small body cable from the Negative cable.

2.) Remove all old Negative Cable.

3.) Clean to Bright metal all attachment points mentioned above.

4.) take the longer of the two cables and attach one end to the Starter and route the cable using wire ties, tape, or wire loom(existing) up to the frame.

5.) Now take the shorter ofthe two cables and route from the battery to the frame using wire loom, wire ties, or tape.

6.) Bolt together the cable to the frame using the old bolt (You cleaned it up, right??).

7.) Connect the small body cable to the new negative cable using supplied crimp connector.

8.) Spray Battery terminal protectant LIBERALLY! on all connections.

9.) Crank it up and check your voltages. They probably will come up!

10.) Make sure the Positive connections are corrosion free also.

NOW TEST your battery and alternator on the truck.

FYI I spent under $20. for both Negative cables and a can of Protectant (red spray on stuff).

Larry

 

Thanks for all the info. I'm going to get the cables replaced next and take all the actions you wrote.

Today I took it to advanced and it was the alternator. I really thought it was going to be hard to replace. But it took me about 15 minutes (after having to return the first one they gave me becuase it was packaged wrong.)

All readings are normal, and i'm back on the road.