Completely over my head mate!! I just drive the thing!! ;oD Claire #2292 --- In doc-uk@xxxxxxxxxxxxxxx, chris@xxxx wrote: > >That is the thermal vacuum switch..... > > >As to what it does?????? I spose it Thermally switches > >the vacuum :-) > > When the engine is cold all vacuum is directed to the warm reg (CPR) then when it is warm that valve directs the vacuum to the distributor advance (via the solenoid which cuts off advance when at idle), got all that..wish you never asked?? :) > > Chris S