O.K.I've read most posts about this and get that this happens in cold weather.
I just replaced both factory batteries at 95K and notice this cycling thing when I first start the engine. It's been rather cold here in th A.M. It even cycles with high idle activated. It Quits cycling after awhile or when driving. My confusion is that I never noticed it cycling with the original factory batteries though it did give me the wate to start light when it was cold enough. Now the Voltage drops from a little over 14v down to about the first line in the charge range indicator and then back to just over 14v. Is this the normal cycling range?? Also, "HOW COULD I NOT HAVE NOTICED THIS BEFORE"???? Could there have been something wrong with the factory batteries?

 

I'm sure someone with an 06 will answer as well, but I believe this is a feature that's been implemented on Rams with Cummins engines for quite a while. I know my 97 does it and I read (probably here on DTR) that it's programmed to turn on below 59 degrees F and cycle on and off for 10 minutes before stopping. It will also stop once the truck's speed exceeds 25 mph. The idea is that it helps provide a little warmth to the incoming air to help promote easier starting and engine warm up when it's cold. My son-in-law has an 08 he bought recently and noticed this happening on his too. You notice when it cycles by seeing the voltage meter reading drop when it cycles on because the heater grid is pulling close to 30 amps of current when it's on. As it cycles off the voltage reading rises back close to normal. My truck has a "Wait to Start" light on the instrument panel that stays on when I first start up when it's cold and I'll see the voltage meter reading low while it's in that wait period, then rise after it cycles off. So, it's a normal thing.

 

Perfectly normal.

3 things will tell you it's happening.

1. relay click
2. voltage drop
3. headlights dim if on

Once you reach (30mph?) if I recall the speed correctly, the cycling stops on my 06. Now I rarely see below freezing temps at home, so if it's colder it may continue to cycle as you drive I just haven't experienced it.

 

Yup, perfectly normal.

 

From day one; I bought my '06 on a cold December night, and on the way home I stopped at a drive-thru burger place and noticed the clicking, dimming head-lights, etc. while waiting in line for my burger. And that was pretty much normal in cold weather for several years. However, I can't say I notice it cycles as much in cold these days... it does it, but seems less. Maybe I just don't pay as much attention??

 

Yeah, I think a person becomes accustom to the grid heater, and tends not to notice unless recent batteries or alternator work has you paying attention to voltage.

 

I have an 06 mine comes on frequently when idling, when it's cold enough.
In my case it runs for 3 minutes or stops when my truck goes over 19 mph, Now my old man has a 2011 and his truck does the same thing, except the lights don't dim, He has the 220amp alternator where I have the 136 amp

If you read your owners manual it will tell you it's normal as well

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I just installed new batteries in my 06 the old ones were stock factory ones {couldn't believe they lasted as long as they did}. I first figured out they were bad because my radio would work off and on, on start up. Now I have no radio problem. Back to your cycling issue, with my new batteries I just noticed my truck cycling yesterday but it was 7* out { complaments of the Artic freeze} and I was parked ideling.

 

O.K. Now I'm seeing the curlly dash light sometimes even when the outside temp is in the 60 degree range. What could be the cause of this? dosn't seem to be a problem. Where does the wate to start heater grids get their signal from? Could this lead to a problem?

 

Normal.

Unless you're below 30 degrees I wouldn't bother waiting, just start her up.

 

Starting is not a problem. Just wondering why it's on in 60* plus temps.?

 

I think it has more to do with emissions than easier starting...

 

My 05 only calls for grid heater when is around 40*? or so. It will click and dim lights until it gets warm.

 

There were two sensors monitoring the intake air temp, one before the turbo (IAT) and one after the turbo (MAP).
Grid heater would kick in when either sensor read below 66F.
There would be NO grid heater operation when both sensors read above 66F or speed above 15mph.

 

O.K. I guess the temps are above 60*F and below 66*F when the dash light comes on, but it seems that, before I changed the batteries the dash light wouldn't come on untill it was below 50*f or less.