All was fine then suddenly turned the key and nothing...all lights and radio are fine...put it on a battery charger 3 hours and it started...drove it a few days later and same thing again...put on charger again but didn't help this time...took out battery and had it tested...came back "good battery"...next took off and replaced starter...no help...any suggestions?

 

Your senario with the "All lights and radio are fine", but woun't start normally is caused by drity battery terminals. Not neccesarily corroded terminals. Just a little oxidation will cause the starter from not having enough amperage to engage and turn the engine over. Try cleaning the battery posts real good, and the inside of the battery connectors. apply a thin coating of dielectrical grease to eliminate future oxidation and give it a try.

 

I have the same problem but with my 2005 SEL Freestar. I'm suspecting a bad battery even though I get 12.54 Volts on the meter because the van starts like a champ when the temp is around the 32F / 0C range, but once it dips below 15F/ -10C that's when it won't crank. Unfortunately I don't have a load tester to test the batteries strength.

 

Most batteries that fail do so when the temp drops. If the connections are good and clean , if that is the original battery, 7 years is good service.Time to consider a replacement.

 

hanky - The OEM lasted 5 yrs, I replaced it in dec of 09. This was a Costco replacement (that I just returned under warranty). The problem stumped me because at first I really didn't suspect a 2 yr old replacement with 100 more CCA then OEM would fail so quickly given that the last 2 winters here were fairly mild for us Canuks.

On top of the fact that my past battery purchases with the Costco brand have been fairly good in performance.

Which brings me to another question concerning my Ford. Does Ford normally have cars that just won't crank if the battery can't provide sufficient load. Reason I ask, with my Honda I get the normal "chug, chug,, choke... with the Van there was nothing.

And because of that at first it made me suspect a lost PATS II code from the key. So knowing how Fords or the Freestar are designed to work (or not) with a weak battery would help me fine tune my exploratory research if I do get an electrical problem in the future.

 

Good thinking ! The year Freestar you have controls the functionality of the PATS via the PCM. And yes if the key lost it's coding you could wind up with the system refusing to ground the starter relay. If replacing the battery with a fully charged one and the vehicle still won't crank, the PATS could be involved.
Is the Theft lamp flashing with the key in the RUN or Start position?

 

Hanky;

The PATS II light on the dash didn't give me any quick flashes or abnormal flashes like it would if the key had lost it's programming, which is why I had suspected the battery as the root problem. But not understanding how the system worked I couldn't dismiss it as a possibility.

I can confirm it was a bad battery now because after I replaced it with a new one under warranty a couple of days later we hit the -17 C mark here, next morning she started up first thing.

But happily now if I have a similar problem I will be able to diagnose things better understanding that the Ford PATS II system disables the starter ground thus not cranking the engine.

Thanks for all the help.

Stefan

 

But happily now if I have a similar problem I will be able to diagnose things better understanding that the Ford PATS II system disables the starter ground thus not cranking the engine.

You know, the longer I work on the PATS system, the more I'm surprized by some of the problems with it.
I've seen many problems with these systems, and the usually (but not always) are traced back to either a halo or a key (though I've had to replace a few processors in various systems to cure them). However, one of the hardest I've ever seen just happend not so long ago.
I was presented with a 07 truck that had problem after problem with PATS. This car had been to every other dealership for repair, with no luck. I verified the problem (the PATS light did flash, and didn't approve the engine for a start). Easy enough. THe code was for an unrecogized key. I programed a new key, and said truck started right up.
Customer takes truck, returns the next day, with the same problem and same codes. Since our service writers really couldn't get more info from the customer, I called him. I found out that he worked in the hospital, in the Xray department.
His job was to wheel people around and get the equipment set up for xrays, MRI, etc. I found out that that the radiation in there was killing his encoder chip in the key, every time.
The funny thing is that the customer never thought about it, and neither did I, until he was asked about it. I'm sure this was akin to an electromagnetic pulse that was killing the chip.
He left his keys in his locker and I haven't seen him since, except for oil changes.
Something to keep in mind.

 

Mark,thanks for that info.
Remember the one where the keys were in close proximity to the vehicle out in the adjacent garage and it kept the modules from going into the sleep mode resulting in a dead battery. These are what makes this field so interesting, it can drive you nuts, in my case a short trip !

 

This is a great point, and as more and more electronics enter into vehicles and our everyday lives this will be a great frustration for diagnosing vehicle electrical problems if the mechanic doesn't keep these outside influence in mind. Obviously this is not something that can be taught in any class as it's just such an invariable. Much like a cold solder on an electrical board is hard to diagnose.

The next 10 years will be interesting as more and more hybrids and electric cars come to market. Soon dealers will need to keep a full on electronics engineer on staff to help diagnose the problems these types of cars will produce. They may even need a software engineer as well. The term wrenching on your car may soon be replaced with "jailbreaking" your car.