I have a 2005 Dodge 2500 with a cummins and when it's cold...less than 40 degrees, the head lights and the lights in the cab, dimm every 4-5 seconds. Does anyone know the cause of this?

 

Grid heater cycling.Once you drive and hit 18 mph it will stop.You just buy this truck?

 

Tis the grid heaters cycling on and off to warm the air going into the engine. Very normal!

These trucks don't have glow plugs. If you look right at the base of the air horn where it bolts on to the intake manifold you'll see the intake grid heater block. Thats where they reside.

Here's some pictures of the grid heater next to Glacier Diesels replacement block.
http://www.glacierdieselpower.com/pr...pf_id=98507-PF

Oh and welcome to the site!

 

global warming.

 

the grid heater is allowing hot air to enter each cylinder to heat them up before take off. Since the engine doesn't have spark plugs heat isn't generated very easily. You will notice from the sound the firing order of the engine. The lights will dim every time another cylinder is heated. I wait until my finishes every time just a note. Aaron

 

Dodge really should have done a better job letting people know about the grid heaters. They should put a light on the dash when the grid heaters are active, more than just the wait to start squiggly. Yea, it is in the manual, but who reads those.

Had I not read about the heaters on there I probably wold have had a heart attack the 1st time I saw the volt gauge and lights cycle.

Remember back in the 80’s when cars had information centers with a diagram of the vehicle and they light up tell in you everything in English? You know like door ajar, coolant low, hood open, low on fuel, and so on. Now they just throw codes; "V9267", oh no! Don't worry that just means your window is down!

 

I was wondering what that was

 

All cylinders are supplied heated air together...Heater draws 90 amps = dim lights.

Firing order is only changed when it is idling and will switch to 3 cylinders and idle up to 1200 rpm to help keep itself warm.

I agree dealers/salesperson should have explained it more, being used to heaters, I knew about it but you do see this question a lot. guess they figure they would find better answers here.

 

Mine did this too. I thought the kids were screwin' around in the truck when I heard the idle increase. I almost yelled at them, when I realized they were all belted in, in the back seat.

 

Mine has never idled up but it does fire the grid heater. Funny thing is it does it at higher temps. I think it was in the low 60's this morning and I got the wait to start thing.... Happens pretty often. Maybe I should take it in?

 

True, all cylinders are supplied heated air together. The engine is spinning way too fast to be able to draw heat into one cylinder at a time. The reason it cycles on and off is to keep from burdening the system for too long.

As far as I know the 2nd gen trucks with a VP44 injection pump are the only ones that will do a 3 cylinder high idle. http://www.youtube.com/watch?v=FZ5-FI9MKL8

3rd gens will idle up to help with warmup but not 3 cyl. If they could I'm certain Marco would enable it with the Smarty.

 

3rd Gen trucks DO NOT have a 3 cylinder warm up feature.It was a 2nd Gen.thing after getting a download for it.It is VERY noticable and defintely changes the tone of the engine and not just a little.If you think the lights dimming on a cold start gets a new diesels owner attention wait until you hear a 2nd gen cold drop three cyls.If your truck did this you'd eaither be calling 1-800 please tow it in or on here posting so fast we couldn't read it.Rough running cold is not a 3cyl drop for warmup.

 

I talked to my Diesel guru today and he said the 3'rd gens do drop 3 cyldrs. if they get cold enough.

 

No one and I mean no one even in the Alaska winter has ever posted on a forum that I have ever read about a 3rd gen doing a 3 cyl.warmup.Very few 2nd gens do it as it has to be programed.They run pretty nasty when it happens.But what ever.