I have a 2005 F350 6.0L that I started having starting issues with over the last few days. It would seem to start okay cold (using the remote start), and would start okay hot. However, starting after sitting for maybe 3 hours seemed to be an issue (wouldn't start on 2 occasions with 15+ start attempts - however eventually started after waiting some time... and seemed to have better luck with the remote start than using the key.) Yesterday I couldn't start it at all, so I towed it to the dealer. Today, they initially called saying they need to replace the batteries (which I found to be odd since they were new less than 2 years ago, and the truck would crank over well, etc.) They said they had the batteries on the charger for 2 hours and were only getting 4.8 volts at the FICM, but it requires at least 9. They replaced both batteries and then phoned to say the FICM was completely fried (only seeing 23 volts from the FICM when requiring 45). After replacing the FICM, they say the truck is ready to go again. I asked the service manager if it would be fine with my old batteries and he wasn't sure. What are the chances I'd need both the batteries and the FICM? It seems to me that they might be trying to hose me for the batteries when I really only needed to have the FICM replaced. I'd appreciate your thoughts...

Thanks,
Mark

 

if you went to a ford dealer you could have asked for a print out of the battery tester. A 2yr old battery can be as bad as one right off the shelf or one that is 5 years old. age of a part has little to nothing to do with how long it will last.
murphy is the only one that knows how long a part will function as it should.
The most common casuse for a failed ficm is low voltage. Also keep inmind that just because the truck seems to turn over fast enugh doesnt mean it is.
the engine needs 150 rpm to light off. so lets say we have that and thats tanking up all the current available oms law says voltage will drop. So as we are cranking voltage drops off to belpw 9volts. Then we have to look at the glowplug controler and its effects on the current draw while cranking.
after all that is said and done the truck must be able to run on its own battery power for the first 2min till the gpcm shuts off.

as far as do you need 2 batteries thats can only be awnsered by an opinionated responce and not by fact. I will say this I try to sell batteries in sets on these trucks and I always sell bxt65-850 wich is the upgrade from the 750's.
When mine go they get replaced by red tops

 

You should load test the batteries individually and then make your decision based on the results of the load test.

Many FICM problems are "at least related" to poor batteries or a weak alternator (IMO anyway).