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How to test intake heater?

11481 Views 7 Replies 6 Participants Last post by  SRT-HAULER
I am wondering if there is a way to test the intake heater. Recently when the grid heater is cycling it is drawing way more than it use to. Before the voltage gauge would drop just below 14 volts when cycling and now it drops to 12 volts when cycling! I disconnected the output from the relay and now there is no drop in voltage.
I checked for continuity from the post where the hot lead from the relay is connected to the heater and to ground and I have continuity? Is that normal or is my heater starting to short out?:confused013:
Also, last week after driving about 10 miles the lightning bolt showed up and dash said check gauges and the volt meter was down below 12 volts.
I have since cleaned and tightened all connections and voltage stays at just above 14 volts after heater finishes cycling. There was no codes thrown. Batteries are only a little over a year old and check out at 12.5 volts each, and I checked them separately and disconnected the cables before checking.
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If you're grid heater is going out, you would have lost the relay under the passenger side battery tray already.. Been there, done that. Dropping to -12v has always been normal in my truck, especially when well below 25F.
Thanks UtahBruteForce, I just don't recall there being that much of a draw before!
Thanks UtahBruteForce, I just don't recall there being that much of a draw before!
Oh yeah, huge draw until truck gets up to speed. Note how the lights in the cab will dim until the truck gets up to temp and the grid heater stops cycling.
I once checked my grid heater with a DC current meter and it draws about 250 amps.
A pretty good load for your alternator and batteries.

Dropping to just 12V? Man somethin' must be wrong with my truck because that sucker drops to like 8 or 10..... with or without the motor running...
when you first start the truck and the curly cue light comes on you'll notice the voltage will go from 8 to like 12 after it cuts off. If you don't notice that, it isn't working.
Mine swings to a 10 ( I put new batteries in) It cycles back and fourth between 10 and 12 for a while. If i don't see the gauge sweeping, then i would start to wonder.
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