1989 740GL Vent Control

Hello all-

I only get air out of the windshield vent. I can slide the controller, but nothing comes out of the floor vents. This also means I can't run the A/C. Is this an easy fix?

Reply to
John
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Look for vacuum leaks around the vacuum relay in the air conditioning unit. The vacuum is picked up from the engine bay and piped through the bulkhead to the air conditioning unit usually near the reveiver/dryer mounting point. It comes from the throtle block via two Nonreturn Valves. One valve is for the cabin air temperature sensor (centre of roof, included in lamp housing) the other valve feeds to the vacuum relay in the programmer and then is connected across to the vacuum switch on the control panel. The Light Green pipe connects the Lower Panel signal, the Brown pipe is for the Air Inlet (Recirculation) signal and the Dark Green pipe is for the Upper Panel signal. Light Brown pipe is for Lower Panel Shutter, Blue pipe is for the Defroster Shutter, Orange pipe is for Air Inlet (Recirculation) Shutter, Red pipe is for the Upper Panel (Vent) Shutter, Grey pipe is for the Water Valve, Black pipe connects the relay and switch together. The last pipe (Violet on 1983 & 1984) White (1985 on) is the source vacuum from the bulkhead inlet. There are slight differences depending on whether Combined Unit + Air Con , Automatic Air Conditioning (ACC) or Electronic Controlled Conditioning (ECC) is fitted.

All the best, Peter.

700/900/90 Register Keeper, Volvo Owners Club (UK).
Reply to
Peter K L Milnes

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