It looks like a double size relay but that is the Idle Control Unit aka
ICU. It is hidden inside the cavity behind the right rear tail light
assembly. Remove the 4 screws and lift away the tail light. Shine a
light in there, all the way in. It is supposed to be mounted on a wall
in there but often is just lying inside.

Mark

Dan N wrote:
> thanks Todd,
>
> I hope that you will find what relay ..
>
> On Fri, Oct 17, 2014 at 2:36 PM, Todd Last <rubatoguy@comcast.net> wrote:
>
>> 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...
>>
>> ------------------------------
>> *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
>>>>>
>>>>>
>>>
>>>
>>
>>
>