Moving from a 240 amp alternator to a 400 amp-- any change to the big 3?

[FatBaldandWheeling]

Your alternator is pcm controlled it will only show 12.6-12.8.

It charges to a higher float voltage based on load and engine rpm.

The voltmeter on the dash will read 12.7 or so at idle and under load, and when coasting will come up to 14.

When I have been hauling uphill for a while, for example, it will become jerky under load. It has thrown U-0010 when it does this. I most recently had this when going over Monarch Pass. I stopped at the top and it had a rough idle too.

But because I coasted down for many miles, I imagine the battery got enough charge that it ceased, and I had enough coasting to keep it just healthy enough.

I am also getting intermittent TCS service lights, which is another indicator of voltage issues. Between all of that and the alternator test, I am confident the issue lies on the alternator.

Sponsored

 

[FatBaldandWheeling]

Now I’m going down a new rabbit hole!
Does anyone know what gauge wiring is stock?
I’m already running lights and a few things and am getting ready to install a winch

This is largely what I am wondering, and more so if it differs for Mopar regular vs. high output alternators

 

[Rusty PW]

If anyone wants to do their own battery cables. Here's a good company to get your parts from. I used them when i redid the wiring in my Power Wagon. I used 2/0 cable.

https://www.batterycablesusa.com/battery-cables

 

[DylanM]

The voltmeter on the dash will read 12.7 or so at idle and under load, and when coasting will come up to 14.

When I have been hauling uphill for a while, for example, it will become jerky under load. It has thrown U-0010 when it does this. I most recently had this when going over Monarch Pass. I stopped at the top and it had a rough idle too.

But because I coasted down for many miles, I imagine the battery got enough charge that it ceased, and I had enough coasting to keep it just healthy enough.

I am also getting intermittent TCS service lights, which is another indicator of voltage issues. Between all of that and the alternator test, I am confident the issue lies on the alternator.

The fact the voltage does come up to 14v when coasting indicates chances are quite good that your alternator is fine. A quick and easy check you can perform for alternator function is outlined in the post I've quoted below.

Considering your U0010 code and some other faults you're experiencing, I'd lean toward a faulty CAN bus connection or possibly the Star connector as being the more likely culprit for your issues.

See below for checking the alternator for function. If it passes the function test, check to see what fault codes are present.

 

[DanJT]

Looks like the same kit as already mentioned above:

You may be right!.... Oops!

 

[FatBaldandWheeling]

The fact the voltage does come up to 14v when coasting indicates chances are quite good that your alternator is fine. A quick and easy check you can perform for alternator function is outlined in the post I've quoted below.

Considering your U0010 code and some other faults you're experiencing, I'd lean toward a faulty CAN bus connection or possibly the Star connector as being the more likely culprit for your issues.

This is really good info. Thank you.

It also informs me about what I should inquire of for other alternators, in case I still want to go to 400 amps

Sponsored