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Discussion Starter · #1 · (Edited)
Looking for some insight on an issue with my 2018 1500 EcoDiesel truck. When the weather turned cold in late November the truck developed an issue. When I autostarted the truck one night and then drove away the dash went blank for a second and then the battery light came on, low voltage. I checked the dash and the voltage was reading between 10.5 and 11 so I headed home but didn't make it. Stopped off at a local Walmart auto center and we dropped in a new fully charged battery. Went right to the dealership. They diagnosed a cracked/not blown 125 amp Mega Fuse and replaced it. (part #68250096AA) The truck was fine for a few days but of course it happened again several days later the same way, cold autostart, drive away and fade to black for a second. Back to the dealer where they replaced the fuse again and said the alt/generator had a short causing the problem. Picked it up and drove for two days and once again, same issue. We are now back for the third time and I just got a call. They said the Mega Fuse should be set at 250 amps not 125 which was installed. I can't find any documentation that calls for that high of a fuse so I am concerned that this is just a patch that could cause other issues. The truck has heated seats, steering wheel and when you autostart the truck all of these accessories come on in the cold weather. It seems to me that there is a wiring issues somewhere and jacking up the fuse to 250 isn't really a solution. What would could this Mega fuse to blow? Currently have 10,000 miles on the truck so covered under warranty but hate to keep going back!!

Thanks for your help!!
 

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Welcome to the forum. There is a 250A fuse at the battery that I think feeds the main power distribution. I think the power steering and cooling fan are both 125A. I'm sure someone here will know for sure.
 

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2015 Outdoorsman EcoD CC w/6.4' 4X4
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Yeap, one of those mega-fuses should a 250 amp fuse. The 125 amp is for the power steering. The third fuse you can't see in the picture is 100 amp for the cooling fan. In the small relay/fuse box in front of the master cylinder, there is three 50 amp fuses for the PTC heaters and a 60 amp for the glow plugs that come through that 250 amp fuse, so if it was only a 125 amp you can see why it would blow.
 

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Discussion Starter · #4 ·
Crash - thanks for the write up and the picture. I will take a peek when they return the truck to verify my set up. I wish I would have taken a picture before to compare.
 

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Discussion Starter · #6 ·
Were you able to solve this? I'm having the same symptoms.
Yes, this did fix the issue. It appears that the original fuse that was installed when the truck was built was the 125. As a result, the dealership kept replacing the blown fuse with the same unit. After a call to FCA it was determined that the correct fuse was the 250. No electrical issues since the 250 was installed. As for the other issues such as the cooler, well that would be a few more trips back to the dealer until I could not take it any more and got rid of the truck. When I traded it the odo read 42,000 miles.
 
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