well when i turn my truck on(after the flash was done) my dash and head lights dim and then go back to regular lighting... the engine also makes this funny sound... u really cant hear it unless u really pay attention...its like it humms for just a sec and the rpms drop like 100 or 200 rpms and then goes back the the normal idel rmps. any ideas what it might be? ima try to see if i can catch the humming with a video..or let ya watch the rpms drop and the idel back.

 

Does it do it a few times after startup for a minute of two? Does the truck change tone but does not sound like it gonna die? It possibly is recirculating. Scared the crap outta me when I first encountered it. But is normal if this is the case. Let us know if thats what it does. Anyone- please correct me if I'm wrong.

 

well... im not sure if it only does it on startup for a few minutes... i will pay attention today since i am gona be driving alot... does not sound like its gona die...just drops rpms and the goes back up. i will update

 

Mines a 2001 and and I guess it has something to do with the block heater or something recirculating. I can stop at a drive-thru shut it down- restart and it will do it again sometimes. What year is it?

 

sounds like your heating elements kicking in watch your volt meter when its doing it, the needle will drop down and then come back up its normal, the heating elements take alot of juice which is why you have 2 batteries.

 

COOKIEMONSTER - You note it was after you had it flashed - but could it coincidently be that the temp where you live is now colder (winter)? The heater element as TROOP mentions draws a lot of current, which slows the engine down a tad as the load is put to the alternator because the batteries need assistance - lights dim, etc. And since the this is driven by the ambient temp, it can do it again if you shut it down and restart it if the engine compartment isn't warmed past the set point.

 

actualy when the grid heater is running the altenator is not supplying any current since the grid heater pulls SOOOOO many amps it would kill the altenator with the load.

when you hit 17mph, or after a few minutes of running the relays will kick off and kick the altenator on to recharge the batteries, untill then the truck is running only on the batteries.

 

Dang - you learn something new every day! I've never known something could load down so much it could kill an alternator.

 

reminds me when we were stranded out in the mountains with my buddys stroker- they tried everything------ including one of them little jump starters- Needless to say it didn't work.... LOL

 

well. . .it is pulling 190amps a piece. . .and there are two of them bad boys in there, so you have around 380amps going through there. even though the altenantor is capable of holding that, you have to imagine the rest of the truck and the power requirements needed would kill it.