I don't think Mark is referring to the voltage upgrades. He is referring to the components replacements and upgrades that provide longer service and more reliability without changing the voltage.

Ed
Ed@ficmrepair.com

:-X22 !!

Need some help guys. I know my FICM is bad I already have a replacment on the way. But I want to ensure that I dont have voltage problems so I dont fry the replacment. Originaly I thought somthing way draining my batteries when the power was off. But after not running for 2 days they are still at 12.5. I got bats tested and my altrrnator tested and they all tested good. But I guess the issue is that my bat's are not reading 12.7. I am just not sure what else to do or if I even have a problem

The 12.5V after 2 days is not bad. More importantly, if you had the batts load tested and they passed, then they are good.

Here is a couple of charts. I put a lot more faith in load tests than voltage charts. Also, if you have anything other than standard flooded cell lead/acid batteries, the charts are off.
http://www.marxrv.com/12volt/voltchart1.gif

http://carnetix.com/regulators/battery-voltages.png

Thanks for the charts. I guess my final question is well my battery light came on while driving and if I remember correctly it only came on during acceleration. Now I got a FICM high voltage code. If that is happening could that cause my battery light to come on because the FICM is drawing to much power.

I don't know. Seems odd that voltage would be low on acceleration. That makes me wonder about your drive belt, and especially the tensioner pulley and spring. Your alternator could actually be slowing down when the engine revs up. I don't think your FICM would cause that.

I get the truck back today. They were trying to say that there was a short in the electrical somewhere since after I drove it down to the mechanic, the CEL went off.

Since it's under warranty, I went with their mechanic. The warranty expires tomorrow and I'm going to test the FICM as soon as I get home and if it shows it's having a problem, I will definitely be sending it off to you

I think that when the previous owner put in the two very small batteries, the low voltage to the FICM could have caused problems in there. Is that possible?

Hmm makes sense but my belt dosnt look bad and when I have taken it of it dosnt seem like there is a lack of tenision in the pully. But how can I check to see if it is applying enuff tension?

Really need some help with this I got my replacment ficm today. But I need to make sure my tennsion is correct on my belt. I tried to look at the wear mark on the pully housing but im not sure what im looking for to make sure my belt isnt streched to much.

If your belt was slipping, it would squall loudly. Only reason for low battery voltage on acceleration is the charging system not keeping up. Have you had your alternator tested?

From reports around here, it seems the tensioner is the item that usually causes problems. Take a look at all the smoothfaced pulleys. If they are polished shiny, they have been slipping.

Yes I had my alternator and batteries test all was good. And under acceleration I figured even if the belt was squeaking I wouldnt be able to hear it over engine noise.

How was the alternator tested? Even if the peak output was diminished, the batteries should be able to hold the voltage up for short durations.

I had it bench tested at auto zone. Is there another way to test it?

So I just pulled my FICM to send to Ed at FICMrepair.com and thought it was interesting that they used 10mm nuts on the front bracket to hold the FICM down and then 8mm BOLTS to hold the back bracket down. Wouldn't common sense dictate stick with one or the other.

Now that it's out, is there any way to tell the stock from an OEM replacement? Not really a big deal, I was just wondering if this had occurred before with this truck.