1973 Corolla TE21 – A/C Clutch Cycle Control
If you look carefully you can see I’ve tie-wrapped the t’stat temp sensor to the evaporator inlet line, just downstream of the expansion valve.
Added male/female terminals on the digistat so I can undo the wiring and remove the stereo again if need be. Everything fell into place. The little tab on the bottom of the plastic surround made reinstallation SO MUCH easier. And it serves as a great place to ground the digistat.
Test drive was perfection. Cycled just as I hoped. In fact, with mid 80’s ambients, the 3.9C low/switch-off temp was a bit too chilly. So I upped it to 4.5C while maintaining the 4.5C degree delta. You can see the read out – as the clutch cycles on, at 9.0C, you can watch the temp drop as the freon is cooling the evap. As soon as the sensor temp hits 4.5C, it cycles off. And because the system is “working”, it continues to get a bit cooler – dropping down to 3.8, 3.9C, and then starts climbing. Back up to 9.0C whereupon the unit re-engages the clutch. Couldn’t be happier.