What controls 92 intake and fuel heaters?

[Niki]

I might be cannibalizing my 92 for a repower project and was wondering 2 things: What controls grid heater cycling and fuel heater operation? I know there's a temp sensor, but what controls the cycling, the ECU? What controlled them in the pre ecu years? I was going to put the grid heaters on a switch/button setup, but I'm kind of wondering what to do w/ the fuel heater. I can dig through the service manual, but I figured someone probably knew off the top of their head here. Thanks

 

[KOG]

Yep, engine computer.

 

[MEby]

our trucks dont have an engine computor, however we do have a pcm. the intake temp sensor inputs to the pcm and tells it at what temps to cycle the heater grids which are operated by two 90 or 95 amp relays. cant remember which.

 

[Niki]

I'm familiar w/ the grid heater relays and all that, I'll probably put them on a button if I keep them at all. As far as the fuel heater, do our trucks even have one? I remember my 95 did, the quality Dodge wiring melted on it. I never looked on any of my first gens, never had the need to. Don't the 91. 5 and up trucks only have a PCM? I've only owned one non IC truck, so I really have no firsthand experience.

 

[dpuckett]

1stGens have a fuel heater right at the top of the fuel filter housing. Most have no issues with it other than leaks when the gaskets get old.



In 89-early 91s, there was a seperate controller that controlled the intake heaters. Whenever the PCMs came along (91. 5 or 92), they took over control of the grid heater circuit.



Daniel

 

[RGramlow]

When I did my repower I looked into the fuel heater and there is a cummins part number if you want to eliminate it and just screw the filter right on there. I just hooked mine up, all that your need to do it supply power to there two wires, it seems to me that there is a temp sensor in the fuel heater itself to turn it on and off when it is cold enough, and I also just put a button in the cab to operate the grid heaters. The black and tan wire is the ground wire for the fuel heater and the Dark Blue one is for positive.

 

[Niki]

When I did my repower I looked into the fuel heater and there is a cummins part number if you want to eliminate it and just screw the filter right on there. I just hooked mine up, all that your need to do it supply power to there two wires, it seems to me that there is a temp sensor in the fuel heater itself to turn it on and off when it is cold enough, and I also just put a button in the cab to operate the grid heaters. The black and tan wire is the ground wire for the fuel heater and the Dark Blue one is for positive.

Thats what I was hoping, that it was self regulated.