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Block Heater

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My truck came with a block heater. It was -20 last night here in Ottawa and no more than -15 today so I thought I would plug in the block heater and see how it worked.

I plugged in the heater cord that came with the truck and checked the voltage =120 v. Was curious about how much draw there is but my amp probe  showed zero amps

when plugged in.  It appears there is no load  Just wondering if anyone else experienced this and if there is something I need to do under the hood to connect the heater .

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If what I've read is correct the block heater cord has a thermostat built into it and it won't even allow the heat to kick in until -18C or lower. My reading included only the diesel engine,   If you find out different let me know!


I can't tell what you drive, might be good to add that info to your profile.

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If your amp probe said 0 amps the block heater was not drawing power. Your input voltage will always read 120 volts but that does not mean that the block heater was on. And Yes it has to be at least -18 for that heater to turn on. I don't like that either but if GM says it's ok to start a -18 engine then. it's ok with me...I've started mine with -30  (no block heater) and it started OK, and always has. By the way diesel means nothing, they only make one block heater and one block heater cord, so it doesn't matter.

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