Actually line to mode switch (from vacuum canister) is quite large: 1/4". Factory original is made of hard plastic, subject to crack. That's what happened to me on trip to SEDOC. Totally barbeque'd driver's side plugs. See pic in #5939's photo album (especially compared to passenger side plugs -- vacuum leak isolated to passenger side rail. That's how I isolated leak so quickly. Hard plastic line has since been replaced with 1/4" fuel line hose). Bill Robertson #5939 >--- In dmcnews@xxxxxxxxxxxxxxx, "David Teitelbaum" <jtrealty@xxxx> wrote: > If the mode switch isn't working first check that it is geting vacuum. > If you hear it hissing and it seems to change the noise when you turn > it into different positions then you probably need to at least > lubricate it. It should turn easily and click into positions without a > lot of force. In Ken's latest magazine he does a whole article on > rebuilding it. You may require a new rubber diaphram. It is a small > round black piece of rubber with channels in it to send the vacuum to > the correct ports. It wears and dries out and cracks. If it is in good > shape a little grease may be all you need. Of course this is assuming > all the actuaters are working and all the hoses are connected. As bad > as vacuum leaks are the mode switch doesn't seem to have all that much > of an effect on the idle (it still shouldn't leak). > David Teitelbaum > vin 10757 > > > --- In dmcnews@xxxxxxxxxxxxxxx, "D F" <funkstuf@xxxx> wrote: > > This is a very interesting letter and it makes me think about a > problem I'm > > having. > > 1.) My system seems to idle properly when cold, then about 1000 rpm > when > > warmed up. > > We have spent substantial time eliminating vacumn leaks but.... > > 2.) My heating switch does not work properly, ie) if I switch from