Engine/Transmission (1998.5 - 2002) Grid heaters cycling too often or too long?

[1empire1]

I just lost a set of batteries due to what I think was the grid heaters. They were the originals with 110,000 miles on them so it isn't a great loss. New batteries installed and all connections clean and tight, my grid heaters appear to cycle on and off between every 5 and 10 seconds when started cold. It will stop after vehicle is warm, but until that point my volt gague looks like a yo-yo while my lights are dimming as if I am flashing the high beams. This doesn't stop with any particular mph but when it is finally warm. Does this appear normal, or is there something I should be checking? I don't wan't to put any unnecessary load on the new batteries or the alternator. Any information is appreciated... Andrew

 

[Huff N Puff]

Its normal for the heater grid to cycle on and of until the engine processor sees the engine warm. Merv

 

[1empire1]

Thanks for the reply. I was just worried watching the volts gague bouncing back and forth between the low line and 14 volts. It seems like an excessive strain on the system... Andrew

 

[Bob Wagner]

If you plug your truck in during cold weather that will help limit the excessive cycling

 

[1empire1]

Thanks Bob. But unfortunately the apartment complex I live in has no place to plug it in. It hasn't been getting any colder than the mid to low 30's lately, but I only drive it about three times a week. So it tends to sit a few days at a time in the cold.

 

[GKinney]

grid heaters

1empire1,, your grid heaters should stop cycling at around 20mph,, at least that is where mine kick off. After that it is clear sailing. Not sure if the 2001's are different, but mine is a 98. 5 and yes the lights will dim big time. The heaters draw 95amps each (X2). My two cents.

 

[TMills]

Andrew,

I live in Cookeville, TN and I have a 2001. My truck does the same thing. I think it is pretty normal. How long do you normally drive after you start it. If only drive a short distance, it doesn't give the batteries time to recharge. I have a very short drive to campus and I just let my truck idel for a short time once I get there. That way some heat has built up in the engine and it is alittle easier on the heater.

 

[1empire1]

Todd, I will usually let it run or at least let it idle for a little while after driving it if I am only going short distances. I know the batteries are charging and they actually lasted 4 years and 110,000 miles on the originals, so I am not complaining. I just don't remember them cycling as quickly last winter and at that time I was still living in New York and never plugged my truck in there either. It seems they are literally clicking on & off every 5 seconds or so. That is the only thing that had me worried if this was putting any extra strain on the charging system. Thanks again...

 

[jungledave]

I thought it said in the owners manual on my 02 that if you start it without warming up the grid heater that it will automatically cancel the grid and will not cycle. I traded in my o2 so I can't check on that, but I am really sure I read that. If this is true then you could start the truck with the grid; if it needs it to start, and then shut it off and restart it without the grid warm up????? Chrysler bought my 04 so I don't have a Dodge Cummins at the present, my little Dakota will work for a while until I can find one that I like. I even remember the manual stating that it will blow a little more white smoke out the exaust until it warms up without the grid heater.

 

[PC12Driver]

The pre start and post start operation of the heater grid are independent of each other. The pre heat mode will run the grid before engine start based on the temperature that the engine sees. Something like 10 seconds for temps between 30-68f, 20 seconds between 10 and 30f, 30 seconds below 15f (I'll have to double check the exact times/temps). So when the truck is plugged in and the intake air gets to be above 68 degrees or so, the grid heaters won't come on PRE start. Also, as soon as the starter is engaged the heater grids will stop their pre start cycle.



Once the truck is running, the post start mode kicks in. If the air being drawn into the intake manifold is below a certain temp (again, I think it's 68F) the grid will continue to cycle on and off (the dimming lights/dipping voltmeter) for 3 minutes or until the truck speed reaches 17mph. Even if you hit the starter before the Wait to Start light goes out which cancels the PRE heat mode, the POST start mode will kick in regardless.



Or something like that...

 

[ntillm01]

My 2001 (early) acts the same way. I had a couple of buddies in the truck the other day when they were cycling. They were amazed that the voltmeter dropped so much and the engine RPMs were pulled down by the load

Yup, normal.



I get the post-heat cycle any time the air temp is below 68F. Even after it's fully warmed up, no wait light on key-up and a re-start. I just get used to it and let it do it's thing.



By the way, my batteries made it 4 1/2 years, 65,000 miles. In my experience, 3-4 years life (not so much the miles) is doing good for batteries in anything.

 

[1empire1]

Thanks everyone for the replys. It does make sense but just wanted to make sure.

 

[Ramafid]

Practical Solutions Diesel Products has a intake heater system saver for our trucks. It will prevent the heater from being cycled after the water temp reaches I think 140 degrees. Even if your truck has been running for hours on end the heaters will cycle each time you start the truck if the temp outside is cold. This product eliminates this. I have had it for about 1. 5 years and love it. Easy install and works great. The webpage is www.psdieselproducts.com

 

[EricBu12]

1 Empire,



go to http://www.psdieselproducts.bizland.com/index.html and get the Grid heater saver. This has 2 water jacket sensors that basically interrupt the relays for the heaters when the engine gets to 70 deg. so even if it is cold outside and the intake air is still cold,,,if the engine is warm, then the heaters won't work. Sometimes my heaters don't run at all in the summer except for the initial key on fro 1/2 sec.

 

[1empire1]

Thanks guys, I will look into that setup... Andrew

 

[Tomscreek]

The grid heater saver looks like a nice thing to have. But why can't a person just install a switch and shut the damn things off after startup?

 

[R-N-R]

I've read about people tapping into the oil pressure wiring to shut off the heater grids after the engine is running. When oil pressure come up, the grids shut off.