I bought an engine block heater a few years ago and had my mechanic install it (I'm too old and fat to be working on cars anymore). Well this winter I discovered it wasn't heating. With a power meter I verified that no current was flowing. With an ohmmeter I verified that the resistance was infinite (should be about 40-50 ohms to get 300W). Also infinite between ground connector and the engine block (I assume the heater is grounded to that wire so you don't end up with a car that is "hot" [pardon the pun] if the "hot" wire becomes loose and touches the engine.

Sounds to me like the connection is completely broken rather than a burnt out heater.

Other than pulling it out and replacing it, any suggestions?

Considering I'd have to pay to have a new one put it, it is probably not worth the expense. I'm looking at getting a replacement for my old pickup - likely a leaf or plug-in hybrid for short trips and keep this car for the long distance stuff. So it would sit a lot more vs now being used all the time.

 

Many block heaters have an in-line thermostat so no wattage is used unless the OAT is below some set outside temperature, often 35F.

 

You might chance cutting off the wires where they bend a lot a few inches behind the plug. I once found thats where I had a open wire. I carefully stripped all 3 then put on a yellow plug with the ground from walmart. It's worked ever since.

I once called a north dakota dealer and the parts man gave me a parts number for my local dealer to order. It shows the 30 something ohms anytime I look at it with the ohm-meter. I was once told the new car model block heaters would not work unless the temperature was less than freezing. To me that would be bummer. A warmer engine when it's 32 degrees is nice and still saves money for mpg. I bought mine a few years before I ever read that.

 

They probably meant 0 Centigrade. Block heaters are made primary for extreme cold, MT, AK, etc, climates but only to keep the engine warmed up for easier starting.

 

That sounds correct, 32 degrees or 0 centigrade. It was many years ago the parts man told me that so it's easy for this old man to forget.

 

Not with the Toyota engine block heater. You plug it in - it works even if the temperature is 70 degrees.

 

I forgot to mention my block heater works no matter what the outside temperature. I just passed along what was told to me by some toyota parts man in Fargo North Dakota.