Sounds like a ground problem.  If the ground wire for the pump also
shows 12v, then it isn't connected to a solid ground.  Do you have a
wiring diagram?

Larry A.

On Sat, Dec 25, 2010 at 5:37 PM, David Vickery <david_vickery@yahoo.com> wrote:
> Well the pump works fine, so it must be something else. �I connected the pump to the battery directly and it runs. �BTW, the other wire is for a valve; it clicks when you give it power like it is supposed to. �And the pump runs when you connect brown and green to battery. �The puzzling thing is that I get 12.x volts at the plug on the same connectors that I connected straight to the battery, but at the plug it won't run. �I even cut the plug and connected directly to the wires to be sure I was getting a good connection. �I don't know how it can show 12.x volts at the plug but not have enough power to run the pump. �I am not that good at using my multimeter but maybe there is a way to diagnose further. Maybe something is loose enough that it shows it has power, but it isn't able to give any current? �I did set the multimeter to 10A and tried to see what the pump was drawing, but with the pump not running, I don't know if the value I got has any meaning
> �.05amps. �If no one has any suggestions, I will be headed to the shop.
> Thanks
> Dave
>
> -- On Fri, 12/24/10, David Vickery <david_vickery@YAHOO.COM> wrote:
>
>> From: David Vickery <david_vickery@YAHOO.COM>
>> Subject: 87 Cruise Control troubleshooting
>> To: vanagon@GERRY.VANAGON.COM
>> Date: Friday, December 24, 2010, 5:07 PM
>> Hi all,
>>
>> Hoping someone can help with my 1987 stock cruise control
>> problem.
>>
>> Background:� My cruise was working well now it won't
>> come on.� I went through the Bentley troubleshooting
>> diagram with a test light and passed the first several
>> checks, including the tests for the clutch and brake
>> switches.� Since I passed those tests, obviously the
>> fuse is fine and the on/off button works.� When I got
>> to the test for the vacuum pump motor, jumping #4 pin with
>> ground it says I should hear the pump come on.� I don't
>> hear anything.� With the ignition on and the cruise
>> control in the on position, the test light lights up but no
>> sounds from the pump in back.
>>
>> I tried another pump today (used and unknown condition) and
>> I don't hear anything with it either.� So I am
>> wondering if it could be a wiring issue or possibly the 2nd
>> pump is bad.� With the #4 jumper in place and a volt
>> meter at the pump in back, I read 12 volts at the plug using
>> + to green wire and negative on the brown wire.� I
>> don't know what the green and white wire is for but I don't
>> get 12 volts when I try substituting that for the green wire
>> with my voltmeter.� When I had the pumps out, I tried
>> putting 12 volts to them directly and I don't hear anything,
>> but I am not sure if I should be using the green/white or
>> green or both with brown going to negative.
>>
>> If anyone knows how I can test the pump directly and what
>> it should sound like if it is working, I would be very
>> appreciative.
>>
>> Thanks, Dave
>>
>
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>
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