High Idle Switch Add

[bruceb58]

I ordered my truck and one thing I didn't order was the high idle switch and now I regret that. I did order the 200A alternator. Ideally I would like a high idle when I am charging my trailer lithium batteries through a 50A DC to DC converter.

 

Anyone add one of these to their gasoline powered trucks after the fact?

[bruceb58]

I ordered my truck and one thing I didn't order was the high idle switch and now I regret that. I did order the 200A alternator. Ideally I would like a high idle when I am charging my trailer lithium batteries through a 50A DC to DC converter.

 

Anyone add one of these to their gasoline powered trucks after the fact?

 

One thing I don't know for sure is if this was even allowed as an option on the gas trucks.

[sno1]

14 minutes ago, bruceb58 said:

I ordered my truck and one thing I didn't order was the high idle switch and now I regret that. I did order the 200A alternator. Ideally I would like a high idle when I am charging my trailer lithium batteries through a 50A DC to DC converter.

 

Anyone add one of these to their gasoline powered trucks after the fact?

 

One thing I don't know for sure is if this was even allowed as an option on the gas trucks.

It is an option on gas trucks, uses cruise control to set it.  Sorry I have no idea about adding on to truck not ordered with it

[Another JR]

I suspect it’s simply a software setting the dealer can change. It uses existing switches, so nothing to physically add.  The question will be whether they will do it on your trim level, but I don’t remember there being a required trim for that option when I ordered my 2021 with it. 
 

You should be able to run a 50 amp dc to dc charger (drawing 55-60 amps) from the 220 amp alternator at low idle, though. 
 

 

Edited June 2, 2024 by Another JR
Typo

[bruceb58]

5 hours ago, Another JR said:

I suspect it’s simply a software setting the dealer can change. It uses existing switches, so nothing to physically add.  The question will be whether they will do it on your trim level, but I don’t remember there being a required trim for that option when I ordered my 2021 with it. 
 

You should be able to run a 50 amp dc to dc charger (drawing 55-60 amps) from the 220 amp alternator at low idle, though. 
 

 

Right now I have a 30A DC to DC and replacing with a 50A. Haven't tried it yet.

[Another JR]

Does your truck have a 120 VAC inverter and plug?  I don’t know if they all have them but my mid-level SLT has a 400 watt inverter. To verify the capability to supply 60 amps at low idle, plug about a 300 watt load into that inverter to draw 25 amps while your 30 amp dc to dc charger is charging in bulk mode drawing 35 amps. You will be able to hear that the alternator has a good load on it. Put a voltmeter on the truck battery terminals and I’m pretty sure you will see that the voltage stays steady at just under 14 vdc at low idle. 
 

 

[gemarsh]

L8T and cruise?

 

Fast Idle UI-Bulletin_82f.pdf

[bruceb58]

1 hour ago, gemarsh said:

L8T and cruise?

 

Fast Idle UI-Bulletin_82f.pdf 311.12 kB · 1 download

Correct...looks like it can be added.

[Another JR]

While I have said I don’t think you would need a high idle switch due to insufficient alternator output at low idle for a 50 amp charger, if you plan to occasionally or regularly do extended charging of your camper batteries by idling your truck, a high idle switch is a good idea. It’s better for the engine to run at 1200 than at 500 to 600 rpm for extended periods.