Dirtleg
Full Access Member
Truck in question is a 2006 F250 King Ranch.
So about 2 months ago my battery light came on while driving one day. It didn't stay on long but I knew it was the start of some issue. I have been closely monitoring my voltage at the ECU since about 2 weeks after that first sign as it kept coming on sporadically after that. Viotage has always been in the 13.7-14.0 range while the light is on. About 10 days ago I drove to the airport (80 miles) and the light was on the whole way. Left the truck there for 9 days while I was on a business trip. Started right up and battery light stayed on the whole way back to my place last night with the lights on. This morning I yanked the batteries and alternator out and had them tested. I did not charge the batteries prior to testing tham as I wanted a real world number after having driven 1:45 minutes with the lights on and the battery light on the whole way.
My batteries are Interstate Mega Tron 850 CCA each. The results were;
Battery 1; Voltage 12.64
Measured CCA 797
Battery 2; Voltage 12.64
Measured CCA 770
Both of them would be passing very well IMO.
On to the alternator;
I do not have a printout but it passed all of the intenal circuitry tests and excitation test. It put out 14.3 volts as well. Passed in good order as well.
Also it should be noted I haven't had any trouble starting the truck or had any need to charge the batteries since they were installed about 20 months ago.
So that leaves an electrical short or other equally difficult to diagnose issue as the culprit here. Does anyone here have any experience with this issue or know where I can find a factory electrical manual online for this truck. Any and all help appreciated.
Also I have asked this on FTE but the overwhelming response was it had to be the alternator or batteries. Apparently it is neither and I am not willing to drop $300 on a new alternator unless I know for sure that is the real problem. So far I am not convinced an alternator will fix this problem.
So about 2 months ago my battery light came on while driving one day. It didn't stay on long but I knew it was the start of some issue. I have been closely monitoring my voltage at the ECU since about 2 weeks after that first sign as it kept coming on sporadically after that. Viotage has always been in the 13.7-14.0 range while the light is on. About 10 days ago I drove to the airport (80 miles) and the light was on the whole way. Left the truck there for 9 days while I was on a business trip. Started right up and battery light stayed on the whole way back to my place last night with the lights on. This morning I yanked the batteries and alternator out and had them tested. I did not charge the batteries prior to testing tham as I wanted a real world number after having driven 1:45 minutes with the lights on and the battery light on the whole way.
My batteries are Interstate Mega Tron 850 CCA each. The results were;
Battery 1; Voltage 12.64
Measured CCA 797
Battery 2; Voltage 12.64
Measured CCA 770
Both of them would be passing very well IMO.
On to the alternator;
I do not have a printout but it passed all of the intenal circuitry tests and excitation test. It put out 14.3 volts as well. Passed in good order as well.
Also it should be noted I haven't had any trouble starting the truck or had any need to charge the batteries since they were installed about 20 months ago.
So that leaves an electrical short or other equally difficult to diagnose issue as the culprit here. Does anyone here have any experience with this issue or know where I can find a factory electrical manual online for this truck. Any and all help appreciated.
Also I have asked this on FTE but the overwhelming response was it had to be the alternator or batteries. Apparently it is neither and I am not willing to drop $300 on a new alternator unless I know for sure that is the real problem. So far I am not convinced an alternator will fix this problem.
