Both.I bought the ETC and thought it was on the rail. Took it off thats how it brokeYo, Pete, I'm confused (should not surprise anyone here), you talk about the reading on your temp gauge after you changed a broken temp sensor, you show a pic of the ect sensor, it has two wires and is mounted to the heater tubes, it communicates with the computer not the temp gauge. The temp sender communicates with the gauge and has one wire.
Which one did you change?