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**pjmoreland** · 06-15-2021, 03:46 AM

I added a second vacuum switch this evening, and it solved the cycling problem. I had to add a diode to the relay latching connection to prevent voltage from backfeeding through the low vacuum switch to the TCC. Without the diode, the delay relay was being bypassed.

I have the low vacuum switch set at 3inHg and the high at 6inHg. I'm going to experiment with setting the low switch even lower so that the TCC stays locked up under heavier load than it does currently. My engine can handle a little more lugging than is allowed at the moment, especially at highway speed.

I've included an overall photo of the harness, but it was from before I installed the diode in the short red wire.

06-15-2021, 03:46 AM	#31
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,334	Re: 700R4 TCC Wiring I added a second vacuum switch this evening, and it solved the cycling problem. I had to add a diode to the relay latching connection to prevent voltage from backfeeding through the low vacuum switch to the TCC. Without the diode, the delay relay was being bypassed. I have the low vacuum switch set at 3inHg and the high at 6inHg. I'm going to experiment with setting the low switch even lower so that the TCC stays locked up under heavier load than it does currently. My engine can handle a little more lugging than is allowed at the moment, especially at highway speed. I've included an overall photo of the harness, but it was from before I installed the diode in the short red wire. Attached Images Last edited by pjmoreland; 06-15-2021 at 03:52 AM.