The main symptom on my 2003 F-250 is that it acts like the batteries are low. I replaced both batteries in January w/ new Interstate batteries, so I don't think that is the issue. When I try to start after it has been sitting for a few days, the starter turns over really slowly. Just for grins, I measured the battery voltage today and just sitting the batteries were 12.1V. The voltage dropped to 9.15V during cranking. After the 2nd or 3rd attempt, the truck usually starts (although slowly) (no smoke or anything). The alternator seems to be working as the voltage shows 14V when the truck is at idle. The slow start seems to be getting progressively worse as the weather turns colder. Also, during the start, it sounds like the alternator is clicking as it turns over (not sure if that is normal or not) Sometimes a check engine light illuminates after the start. Autozone told me the fault code was an undefined electrical issue. After the truck starts, and idles for a minute, successive starts are normal - it is only when it has been sitting for 48hrs+ that it starts slowly. I am pretty much a novice/newbie at car diagnosis/repair, but thought I would see if anybody had any thoughts on something(s) I should look at before I take it to a professional.

Was also wondering if there was some way to determine if there is a load on the batteries, in effect wearing them down, when it is off. (something like leaving your dome light on for days on end).
Thanks

 

Autozone will not be able to read the codes as these trucks are not obd II compliant. You will need a shop with a high end scanner or an ae software for yourself. They can load test the batteries though and tell you if they are still good.

Even if they look good, take the battery cable ends off and clean them really well and reinstall. Simple oxidation will make these trucks not start very well.

To check for a draw, hook an ammeter in line with the cables and see how many amps its pulling with all the doors shut and the key off. Pull the + cable off both batts and the connect the meter between the batt post and cable on one of them. Leave the other disconnected.

U can also feel the alternator after it has sat for a couple days and see if its warm to the touch before you crank it. If its warm, its bad.

 

Thanks carltonwebb. I will feel the alternator in the morning. What part of it should be warm (if its bad)? Top, bottom, left, right, entire piece,etc?

The battery cables look really clean. I cleaned them really well when I installed the new batteries at the beginning of the year and covered them w/ dielectric grease. No sign of oxidation or anything on the battery terminals. Did you mean disconnect the other ends of the cables where the black cable grounds to the chassis and ...not sure where the red cables connect??

I will try to hook up the ammeter the way you described. So I disconnect both + cables and hook the ammeter between the + battery terminal and the battery cable, and leave the other + battery cable disconnected? This seems odd to me, but as I said, I am no Einstein when it comes to things electrical. Should there be zero draw w/ the key off, or a tiny bit? (how much?) Will let you know what I find out tomorrow.

 

there is a video. On 2nd thought, Use the ground side its safer. I always do the + side. You can get the clip on ammeter he has for around $30 at sears if you do not want to disconnect the cables. I would say anything over .2 amps is too much. Your memory circuit on radio and VSM will still draw minute current.

Clean the cables anyway. I am not talking about the corrosion, I am talking about oxidation which is usually almost colorless. My truck goes through it every year when it gets cold.

 

The whole thing will be warm.

 

Felt the alternator...it was cold.
I disconnected both negative battery cables and performed a parasitic draw test on both battery.
The pax side battery was showing .34 Amps. The drivers side battery was showing 1.12 Amps. That seems a little high for the truck just sitting cold, no? What are my options going forward?

 

was your underhood light on?

 

Slow start, first thing I would suggest looking at, same thing every year. Check how tight you terminals are, make sure one is not craked. if you can even slightly move a battery terminal, it is too loose for these beast.

Every year ( except this one ) I had to go under the hood and clean my terminals, and paint them up. last year I went out and bought new cables.. I have not had an issue YET..

 

Underhood light is not on (bulb is removed as is the dome light bulb). As far as loose or dirty battery cables, do you think I would still have that much of a parasitic draw w/ the ammeter (neg wires disconnected)? I will clean all 4 of the battery terminals, but I really don't think this is the issue as they appear very clean and tight.

 

Just see if you can move them..If you can move them, then yes.. More then likely, you have your problem.

 

Can't move them. They are tight. I did clean the battery terminals and the cables this afternoon. I still think there is something putting a constant drain on the battery. While I had all of the cables disconnected, I measured the voltage on the batteries and one battery showed less than 11 volts and the other showed about 12.2 volts. And the current draw when I hooked things back up was the same about .34 amps and 1.2 amps respectively. The truck did start up fairly normally even w/ less than optimum voltage. It was a little slow, but not nearly as slow as sometimes, and it did NOT generate a check engine light. Are the only things that are supposed to be powered w/ the truck off, the radio clock/memory and vsm? I have suspected vsm issues in the past, but have not dealt w/ them as I have been able to tolerate them. I suppose the vsm could be deteriorating further and it sucking power when its not supposed to, or more power than its supposed to.

 

I measured the voltage on the batteries and one battery showed less than 11 volts

Looks like your problem right there. Have that battery tested.

 

I have the same issue with Interstate batteries on a 2003 F350. The batteries and alternator tested good, but I am still wondering if it is the battery. Had a Dodge van a few years back that had an Interstate battery. It had several electrical issues that miraculously disappeared and never returned when I replaced it with a battery from a different company. I am thinking about doing the same with the F350.

 

*UPDATE*
I did take both batteries in and even though they were less than 9 months old, turns out that one battery had a "bad cell". They said the other battery was fine, but that on cold mornings, there just wasn't enough CCA's to adequately get the truck started. I am still a little miffed about the amperage draw when the truck is off. The guy at the battery place, said to wait for at least 5 mins after you shut the truck off as the computers have to spool down or something like that. I was eventually able to get right around 500mAh draw with the ignition off, which I guess is about normal. Thanks for your thoughts guys!

 

when changing battery's. you should replace them both. if one go's bad it puts a strain on the other. it wont be long until the other battery go's bad 90% of the time.