Our '69E Targa rear glass has and came (per the COA and the original glass I have) with a single stage defrost. I don't have the rear defroster switch. I see the dual stage switches offered occasionally, but is there a single stage switch for the single stage defrost or did they just use the dual? If they did install a single stage switch I need one and would appreciate any leads or the part #. Thanks in advance to the brain trust.