Melting block heater cord?

Bad plug. I had to replace mine with 20 amp heavy duty plugs.

 

Not sure exactly what you are saying?? If you used a 12 gauge extention cord or not?

Corrosion can lay in on the back of the male plug connection and break some of the wire strands and cause a power surge.

Make sure you plug into a 20amp AFCI (arc fault circuit interrupter) if the source is prewired with 12 AWG. It's more sensitive than a GFI. It would of prevented the melting. $20-30 is cheaper than replacing the truck. You can either change the outlet or breaker.

 

Every time this has happened to me, it has always been the extension cord, not the block heater.

Get a new cord and try it.

 

Mine had the type plug in that mounted to the truck body. Corrosion from salt had gotten under the rubber behind the plug and eat the wires some. After I put on a good hardware store plug I had no more hot connections.

 

The melting is due to bad connection at that spot. When there is any kind of bad or weak connection the electricity has a harder time passing through due to the increased resistance. Resistance causes heat, enough to melt your cord or plug.

 

Make sure male & female elec ends are tight. if they come even slightly apart, an elec arc will get the ends hot & melt.

 

Be sure to replace the end on the block heater cord too.