Hi I have a problem with my cab lights dimming and the voltage is at about 12 volts at start up but come up gradually after running down the road to a more normal voltage of 14.5.
When I start the engine the volts are at 12 and I can hear a slight engine change in idle and then the cab lights dim and then the engine changes again and then the cab lights get bright again. anyone have any idea what this may be the dealer said its the grid heaters running but its been very mild here in Jersey and it didnt do it when it was new.

Also they did the reflash on the fuel mileage today they adjusted the ECM or something like that. But I am waiting on the wife to take me to pick up my truck. Thanks any help would be great.

I forgot I have a 2004.5 dodge CTD quad cab short bed with snow plow prep and tow package

 

Are you new to the Cummins? If so, then I'll suggest the grid heaters operating. Your truck will cycle the grid heaters on and off for 3 minutes when it's cold out... or until you hit 18mph to help the engine warm up quicker. If I remember right, they come on when the temp sensor says it's below 59*; has it been that mild?

These things draw an incredible amount of power from the system and you'll see the battery go down to about 12v or so and all your lights will dim when it's on and brighten when they aren't drawing full current. Your windows, wipers, seats etc will all operate slower than normal when the heaters draw their necessary current.

The grid heaters in our trucks take the place of/do the basic same function as glow plugs in other diesels.

Hope this is all it is and nothing more serious. Apologies in advance if you already knew about the grid heaters and this is something else.

 

No apologies needed I am new to diesels and need people like you to help me I dont trust the dealers all that much. Here I can get a straight answer. I didnt notice this happening untill I was in maine hunting this year I have about 10,000 flawless miles on it so far and am very happy to date. Thanks for you help.

 

I agree grid heaters...

 

Saw this the very first time I moved it from the lot. We had snow in July, and a very cool August this year. So far, my lowest "unplugged" startup has been 18 degrees. The dealer said "warmup elements - not to worry"

 

Yep the GRID Heaters are the culprit. For 3 minutes after startup they will do that at anytime when the temp is below, I think, 68 according to the info on the visor.

 

Correct!! You may also notice the idle gets a little less smooth too. All normal..

 

Snow in JULY? Good God, the heat index routinely exceeds 100 down here in July! Hard to imagine we're in the same country with that kind of temperature difference.

 

Along with the grid heaters there are fuel heaters in the filter housing. When its cold all of these things draw power. Nothing to worry about.

"Drive it like you stole it."

 

Definitley grid heaters, they stay on till certain temp criteria are met or you get up to a certain speed that escapes me at this time. Something like 25kmh.

 

About mid-July, it dropped to 25deg here in Star Meadows (55 miles from the Canadian Border) Snowed a bit. Blew out the external faucet on the back of the house because I had a hose screwed on.

Definitely weird weather this year... but no fires - thank God.