Originally Posted By: Ross
This past month I had a stock block heater installed in my 09 saturn outlook. My saturn dealer gave me a choice of a gm thermostat controlled cord for $130 or a gm non thermostat controlled cord for $28. I went with the non thermostat cord.
The thermostat is in the male part of the cord and only turns on when the temp is below 0 F.
I posted this info on the acadia forms, and a few members took issue with what I had done. I was told that the thermostat was there for a reason? Apparently on some gm cars/truck the computer does a test on start up. It tests the coolant temp against the air inlet temp. If there is a big difference, the car may throw a code, thinking that one of the two sensors is bad. I was told that below 0 F, the computer either ignores the difference or doesn't to the test on start up. So, this winter, I will test this out at different temps to see if I get a CEL if I use the block heater above 0 F.
I searched around and could only find a few examples of this happening and it was mostly happening with GM trucks.
I don't think I will have any issue and if I do, I will limit the block heater use to temps below 0 F.
Don't worry about it Ross... The thermostat controlled cord is only offered for ease of use and money savings. The non-thermostat controlled cord will simply heat up the block heater in any temp, whereas the controlled cord can be plugged it at all times but will only activate when absolutely necessary. This is really only to make things easier for the owner, and to take away some of the guess work of using it (and obviously to cut down on electrical consumption - which is minimal anyway).
Your car will not throw a code with the non-controlled block heater cord, especially if GM offers both cords. Some people are just misinformed. Plus, I wouldn't want the controlled cord either, since I prefer to start using my block heater in any temps below 25-30F.
