Help needed: '03 F-250 electrical issues...

[Hasselhoss]

Get an amp meter and put it in series with the positive cable from the battery (do not try to crank). Observe current flow. Begin removing fuses one at a time and look at current flow. When the flow stops, you found the offending circuit. Find out what that fuse goes to and start troubleshooting.

 

[lftd&pwrstrok'n]

Where did you get the alternator from? what kind of batteries are in it? From the sounds of it your issues is intermittent and not very consistent i.e. random never know when vs every two days.
Have you ever noticed the door ajar indicator coming on while driving? The door switches are a common failure and can cause the dome light to come on and stay on after the truck is parked.
They snap (twist in) the door latch similar to a small light bulb socket. Also could be a bad diode in the Alternator causing an intermit. draw or could just be some crappy batteries (happens alot).
Wish you were closer to Canton I could run a few checks. These intermittent electrical issues can be a real pain to track down. You can always try pulling the fuse for the dome lights but be sure to check what else is on that circut.

A local shop installed the alternator, so not sure where it came from. Batteries are the Duralast Gold (I think) from Autozone. I am sure that there are no lights staying on (except perhaps the under hood light) because I always check before I leave truck. I need to check fluid level in batteries (as I haven't done that yet--dark when I tried to crank it).

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Get an amp meter and put it in series with the positive cable from the battery (do not try to crank). Observe current flow. Begin removing fuses one at a time and look at current flow. When the flow stops, you found the offending circuit. Find out what that fuse goes to and start troubleshooting.

I will give this a shot tomorrow. Thanks.

 

[Hasselhoss]

A local shop installed the alternator, so not sure where it came from. Batteries are the Duralast Gold (I think) from Autozone. I am sure that there are no lights staying on (except perhaps the under hood light) because I always check before I leave truck. I need to check fluid level in batteries (as I haven't done that yet--dark when I tried to crank it).

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I will give this a shot tomorrow. Thanks.

Have you uses an amp meter before? It's much different than hooking up to test for voltage or impedance. The line must be disconnected and The meter must be in series and there can be no alternate paths. In other words, you disconnect the battery cable. Hook one end to the meter lead and hook the other meter lead to the battery. BEFORE you do this, pull the cable and touch it to the battery quickly. If it sparks Big then don't hook your meter up you'll blow the fuse.If it sparks big, your voltage regulator is shorted to ground on the alternator and will need to be replaced.

 

[lftd&pwrstrok'n]

Have you uses an amp meter before? It's much different than hooking up to test for voltage or impedance. The line must be disconnected and The meter must be in series and there can be no alternate paths. In other words, you disconnect the battery cable. Hook one end to the meter lead and hook the other meter lead to the battery. BEFORE you do this, pull the cable and touch it to the battery quickly. If it sparks Big then don't hook your meter up you'll blow the fuse.If it sparks big, your voltage regulator is shorted to ground on the alternator and will need to be replaced.

No, I guess I haven't. Actually, I know I haven't done anything close to the above described methods. I really am not mechanically inclined at all. I have a Dr appt tomorrow and will drop the truck off my the shop on the way and let them take a look at it. Beats me blowing something up.

 

[auburnfan04]

It's much easier and safer ( for your meter) to use a test light. Any amps that will light the bulb up bright are too much. You can accomplish the same thing by pulling fuses and watching for the light to go out. Disconnect the negative cable and hook the light from the negative cable to the negative post.

 

[JDG.]

Try this before all the crazyness starts. Go to autozone and have them test the batteries and alternator for free. Don't buy the alternator from them if they say its bad though.

 

[quality1const]

I'd lean towards a bad cell in one of the batteries. Had the same problem with my 7.3L last year. They were Duralast Gold's as well.

 

[Lockout]

It's much easier and safer ( for your meter) to use a test light. Any amps that will light the bulb up bright are too much. You can accomplish the same thing by pulling fuses and watching for the light to go out. Disconnect the negative cable and hook the light from the negative cable to the negative post.

Back in the older days this would work but with all the modules and relays and computers that will keep some sort of amps and draw this would not work accurately.These new vehicles you will have to use a amp/draw meter diagnostic device.

I agree with jdgreen get it tested before you try to much as you might mess with the wrong things and cause more headache and problems...These aftermarket cheap ass battery's and alternators are to blame...

 

[lftd&pwrstrok'n]

Thanks guys. I already talked w/ my mechanic and he is expecting me in the morning. I will drop it off w/ him and see where to go from there.

 

[Constitution Hour]

Well as has been said here already, the batteries would be the first suspect, and the duralast are not a good choice of battery IMO. Regarding the lights staying on, they won't. I have seen many a bad door switch turn the light on hours after the vehicle was parked and locked up. Never assume.