My radiator fan does not turn on when engine warms up. It did however turn on when I turned off the ignition. I thought to myself..."what the #&!$"? I turned the ignition back on, and the fan fired up. So again..."what the #&!$"? Thanks in advance.

 

Sounds like the t-stat switch.

https://honda-tech.com/forums/honda-accord-1990-2002-2/four-water-coolant-temperature-temp-switches-sensors-cel-code-6-a-2417412/

 

Both the Mugen switch and Mugen t-stat are about 3,000 miles old. This only happened after my wire tuck, so I have to believe it's a wiring issue (although, I only cut and extended one wire at a time so I know I didn't cross any wires).

 

I'm updating my old threads for the benefit of future googlers. When relooming my engine harness, switched the connectors for ECT A and ECT B. Swapping them back fixed the problem.