I had this problem and I want to say it had something to do with a relay behind the rear cabinet. I will have to search my notes...

----- Original Message -----

From: "Dan N" <dn92610@gmail.com>
To: "Rubatoguy" <rubatoguy@comcast.net>
Cc: "List, Vanagon" <vanagon@gerry.vanagon.com>
Sent: Friday, October 17, 2014 11:18:54 AM
Subject: Re: High idle w. A/C on... please help

yes Todd AC is connected and working well, no leak, gives cold air - except high idle (2K RPM) and fan on medium speed.

thanks

On Fri, Oct 17, 2014 at 11:13 AM, Todd Last < rubatoguy@comcast.net > wrote:

Is your AC connected and working? Belt connected on the A/C compressor?

From: "Dan N" < dn92610@GMAIL.COM >
To: "List, Vanagon" < vanagon@GERRY.VANAGON.COM >
Sent: Friday, October 17, 2014 11:00:02 AM
Subject: Re: High idle w. A/C on... please help

thanks Mark...

on my others Vanagon I get 1200RPM at idle with A/C on and not 2K RPM, I
think it's too much but 1400RPM is acceptable.

dan

On Fri, Oct 17, 2014 at 10:34 AM, mark drillock < mdrillock@cox.net > wrote:

> The idle is supposed to increase when the A/C is on. There is a wire
> from the A/C compressor clutch over to the idle control unit so the idle
> control unit will know to increase the idle speed so the A/C doesn't
> stall the engine. I don't know what the idle speed rpm increase is
> supposed to be but maybe someone else does.
>
> That year should have the later trinary pressure switch and this could
> be giving a false indication of a need for medium fan speed. Or maybe
> someone could have fooled with the wiring to make it do this?
>
> Mark
>
>
> Dan N wrote:
>
>> hi all,
>>
>> 1990' Carat - recently purchased - rebuilt engine - smooth idle 950 RPM -
>> A/C recently serviced, cold air, new fan switch.
>>
>> When I turn the A/C on the idle jumps to 2000 RPM - the fan goes to medium
>> speed all the time.
>>
>> What part or parts that triggers the idle?
>>
>> What part or parts that triggers the fan?
>>
>> please help - I search in the archive and only found an April 2000
>> article
>> about this..
>>
>> many thanks in advance
>>
>> dan
>>
>>