hey guys, this is my first question on here and am hopin for some info. i'm having an issue with my intake heater grids sticking on. it's done it 4 times since i've owned the truck (3yrs). its not really consistent either. its happened on cold start twice while the heater grids are cycling and its happened twice while driving. i'll just be driving along and the heater will turn on and stay on. also when it happened while driving it would not turn off when i shut the truck off. the first two times it started to melt the power wires going from the heater relays on the left fender to the grids. the second time i had to replace the wires because it melted the fusible links in the wires and burned both wires through. i also replaced both relays because i noticed the relay cases were both cracked. i thought this may have been the problem but to make sure i wired in a light to both wires coming off the relays going to the grids so i know when there both on. it happened two more times after this and both times where while i was driving. both of these times i pulled over and removed the trigger wires from the relays so the relays would turn off. its been about a year now and it hasn't happend since. i know a lot of guys with dodge diesels and none of them have said anything about it happening to them and thought it was wierd. also my dad had it happen once to him while driving fom virginia to our home in new york. only happened once and it was while pulling out of a truck stop. we disconnected the trigger wires and left it disconnected for the rest of the trip. hasn't happened again on him. his is a 2001 HO 6sp 3500. doesn't have to be cold out either but three of the times it happened to me it was cold the other one was when it was raining and warm. i'm sorry for the long thread but i'm kinda hoping someone maybe able to shed some light on this situation. thanks.

p.s. i love the site. it gets very addicting. its nice to share info with others in the CTD world.

 

You might check your Inlet Air Temperature Sensor (IAT) on the drivers side of the head at the rear...above the stock lift pump location.

 

yeah thats what my dad said and thats were i was going to go. i really haven't had the time to really get to involved with it lately but that will be a starting place it think. thanks

 

If you can pull of the wires feeding the relays and they turn off, that means that something is turning them on. Find what is keeping them turned on, possibly the ECM.

 

yeah i definetly know its not the relays and the grids. i just need to figure out what is telling the ECM to turn the relays on or like you said maybe its the ECM itself causing them to turn on.