You can also use a voltmeter connected with the actual circuit and test the complete system. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Larry Alofs
Sent: Thursday, July 21, 2016 8:12 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 1991 Carat - the drama continues

You can test switches like these with an ohmmeter, a bicycle pump, and a pressure gauge.

Larry A.

On Thu, Jul 21, 2016 at 7:55 PM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> It would be very rare for an oil pressure switch to completely fail 
> out of the box. I've seen them be way out of tolerance not yet one 
> that didn’t work at all. It is possible that you really have a wiring 
> issue and that moving stuff made the system work for now. This is 
> usually the case when someone thinks they fixed an operating problem 
> by replacing the temp 2 sensor. Simply wiping the contacts or moving 
> the wires where crimped in those connector terminals did the fix.
>
> The connector for the oil pressure switches on the left side of the 
> engine tends to corrode and make a very high resistance connection 
> causing false oil pressure alarms. A bad engine ground can also cause 
> a back feed triggering the system to falsely alarm. Using a meter a 
> real diagnoses could have been made without simply changing parts and seeing what happens.
> Who knows, maybe you have a switch that was operating at the high end 
> and that engine has an oil pressure problem.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On 
> Behalf Of John Rodgers
> Sent: Thursday, July 21, 2016 9:38 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: 1991 Carat - the drama continues
>
> No, what I'm saying is, a brand new switch failed right out of the 
> box. I supplied the new switches - and a new thermostat - to the shop. 
> They were quite old, having been gifted to me when a  local VW shop 
> closed. I was gifted many genuine VW parts. Though old,  but still in 
> the original boxes, I saw no reason not to use them. That one switch 
> failed. New out of the box failures are not new to me. I once had a 
> new piece of avionics navagational gear that cost $5000 fail on the 
> first flight after installation only 10 minutes from the airport after 
> departure. Frustrating to be sure. But an easy fix by exchanging for 
> another new one. Took a little time to R&R the thing. But other than that, no problem. Same with tne switch.
>
> John
>
> On Jul 21, 2016 04:03, "Frank Condelli" <RAlanen@aol.com> wrote:
>
> >         Soooo, what you’re telling us here is that your shop rebuilt 
> > and installed an engine and did not install NEW $6.95 oil pressure 
> > switches and make sure the wiring to those two switches are in 
> > PERFECT
> condition.
> > Better tell us the shop to avoid !
> >
> >
> > > On Jul 21, 2016, at 12:00 AM, Automatic digest processor <
> > LISTSERV@GERRY.VANAGON.COM> wrote:
> > >
> > > Finnaly got the new engine installed, tested and everything seemed 
> > > to run fine. Water was used for cooling while testing. Drained it 
> > > out today, dragged out my bong filling devise, and proceeded to 
> > > fill the system with
> > > 50/50 mix of glycol and water. Once filled, I took it out on 
> > > Interstate
> > 20
> > > eat of birmingham for a test run. Couldn't have asked fo better 
> > > performance. As I rxited the highway  at a cloverleave, my heart 
> > > sank! As the van slowed the oil light came on with the warning horn.
> > > What tne
> > heck!
> > >
> > > There was a big grassy area in the cloverleaf, and I coasted to 
> > > stop out
> > in
> > > it. I was puzzled. I waited a few minutes, then started again.
> > > Goosed the throttle up a bit, and as the rpm dropped the oil light 
> > > came on again an the horn sounded. Little bells started ringing. I 
> > > thought, lets try this again, but take the rpm to 3000 rpm. I 
> > > started the engine, held at 3000, and the oil lighT DID NOT come 
> > > on.as I let off on the gas, and as the
> > rpm
> > > hit 2200, the alarm sounded and the light came on. Aha, I thought, 
> > > I've
> > got
> > > you now! Dynamic oil pressure fault. Started the engine, held it 
> > > at idle
> > -
> > > no light and alarm. Push the rpm to2000 and held, still no alarm 
> > > an
> > light.
> > > Increased rpm to 2500, no alarm, no light. Let off on the gas and 
> > > whenn
> > the
> > > rpm dropped to 2200 the light came on and the ala3rm sounded.
> > > Definitely that dynamic oil pressure system! Drove it back to the 
> > > shop at 2000 rpm
> > and
> > > under. No problem, no light, no alarm.
> > >
> > > Tomorrow it gets a new switch!
> > >
> > > Hopefully the vehicle will be ready then for the rest of it's 
> > > restoration
> > >
> > > John
> >
> > Cheers,
> >
> > Frank Condelli
> > Almonte, Ontario, Canada
> > '87 VW Westy, '00 Kawasaki 250 Sherpa, "98 Ducati 750 Monster & 
> > Lionel Trains (Collection for sale 
> > <http://frankcondelli.com/trainsal.htm>)
> > Frank Condelli & Associates <http://www.frankcondelli.com/> - 
> > Vanagon/Vanagon Westfalia Service in the Ottawa Valley BusFusion 
> > <http://www.busfusion.com/> a VW Camper camping event, Almonte, ON, 
> > June 02 ~ 05, 2016
> >
>