I have one of the old Envi units. I tried to hold down the button on the transmitter for >9 secs and the LED light never starts blinking rapidly. It does flash every 6 seconds or so, but never goes into the "pair" mode. I tried changing the batteries - no help. I also tried leaving the batteries out for a while, then trying again - no help.
Any other tips or tricks to get the transmitter into pair mode?
While waiting for the post to be approved, I found a way:
I opened the transmitter and shorted the two legs of the momentary button. Shorting for >9 secs put it into pair mode and it's back working again.