If this describes what you're experiencing when lighting off the Cummins on these frosty mornings,.......
Don't worry, it's normal.

The Cummins uses a pair of 12 volt grid heaters in the intake tract
(imagine two large toaster elements glowing bright red)
that preheat incoming air for easier combustion.
The Ford & Chevy use glow plugs inside the combustion chamber.
As the relay cycles the grids on & off, the large amp draw causes the volt meter reading to drop, and the lights to dim when the relay turns on the juice.
The relay timer will turn off the heaters when the intake temps hit a preset limit, or when the vehicle exceeds a preset MPH (usually between 15-25 mph).

Don't panic
.........just another of the experiences you can chalk up to being a member of the Cummins Club.

 

Here is a link to our tech articles section for the 2nd Generation 24 Valve Rams.

2nd Generation 24 Valve ISB Engine & Drivetrain Tech Articles

Lots of good articles and information there such as :

-Common Part #'s- Part #'s for a lot of common items such as air, fuel, and oil filters. Belts, hoses, thermostats and sensors and other parts. Includes year model specific part numbers.

-Valve Adjustment Procedures- A complete how-to guide to adjust the valves on a 24V ISB.

-47RE Automatic Transmission Band Adjustment Procedure- A great guide on how to adjust the bands on a 47RE while servicing it or while changing the fluid.

-How the 47RE works- Great article explaining the ins and outs and history of the 47RE.

APPS Reset Procedure A guide to reseting the APPS sensor.

Performance Upgrades : A great guidline to getting more performance out of your Cummins

 

-How to Re-program Keyless Entry Fobs

HVAC Troubleshooting and Principles of Operation

 

Once enabled, idle speed will slowly ramp up from 800 rpm to 1200 rpm when all of the following conditions are met:

1. Intake Manifold Temperature less than 0°C (32°F) and,
2. Coolant Temp is less than 60°C (140°F) and,
3. The Transmission is in Neutral or Park and,
4. The Service Brake pedal is not depressed and,
5. Throttle = 0% and,
6. Vehicle Speed = 0 mph

Additionally, if Intake Manifold Temperature (IMT) is less than -9°C (15°F), and all of the parameters above are met, three of the cylinders will be shut off upon reaching 1200 rpm, creating a slight change (yea right!) in engine sound which is normal. This allows the engine to create increased heat in the cooling system, allowing more rapid engine warm up and cab heating.

Both features will automatically disable when one of the following occurs:

1. The Automatic Transmission is placed in gear (forward or reverse) or,
2. The Service Brake pedal is depressed or,
3. Throttle position is greater than 0% or,
4. Vehicle Speed is greater than 0 mph or,
5. Coolant Temperature is greater than 79°C (175°F).

Engine speed will return to normal operation at 800 rpm. If the engine continues to idle and coolant temperature is at or below 60°C (140°'F), the feature will reenable. In order to operate properly, the Accelerator Pedal Position Sensor (APPS) must stay at idle.

 

Heres an article for installing Marinco sockets to power your block heater :

https://www.dieseltruckresource.com/...d.php?t=167831

 

Understand that the overdrive lockup clutch is controlled electrically by the PCM.

The effect that is occuring is known as a "ground loop". Ground loop cause unwanted electrical "noise" on electrical and signal lines. The lockup clutch is controlled electrically and a noisy control line will make it "hunt", or shift repeatedly in and out of overdrive once you get around 45 MPH or so (actual speed the shift happens vary based on axle ratio and tire size).

http://en.wikipedia.org/wiki/Ground_loop_(electricity)

Dirty connections, corrosion, and loose connections all contribute to ground loop. Fixing it is easy though. Generally involves cleaning ALL ground connections affecting the transmission and controlling it. Batteries, frame connections and the PCM on the firewall all need to be cleaned.

IMO tin foil shielding and power filters are simply band-aids that mask the underlying problem if left unchecked. And like I said before a simple cleaning with a wire brush and a piece of sandpaper will normally fix the problem with the lockup clutch.

Here is one of my posts from another thread involving the same issue.

I had the lockup issue and it immediatly was solved after cleaning the grounds.