I guess the reciever/dryer, the little rascal on the extreme passenger side firewall with the sight glass on the top.
Just one set of wires going to it. No other wires near it.

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Ncnetman
1978 300cd fresh paint
1965 Mustang
1968 Torino GT fastback
2015 VW Passat TDI
1969 Ranchero- project
1974 240d 4-speed -for sale
1976 240d - for sale
1990 6.2 Suburban 194k-getting a 6.5 turbo
2008 Duramax Silverado-totaled
1959 Chev 3100 Fleetside - sold