Date:         Fri, 11 May 2007 04:11:30 -0500
Reply-To:     Matt Roberds <mattroberds@COX.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Matt Roberds <mattroberds@COX.NET>
Subject:      Re: evaporator cabinet in place now have pressure switch/50 amp
              fuse blown-long
Comments: cc: David Clarkson <dvdclarksn@AOL.COM>
In-Reply-To:  <20070510165508.HJDE16909.fed1rmmtai110.cox.net@fed1rmimpi03.cox.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

> From:    David Clarkson <dvdclarksn@AOL.COM>
> Date:    Thu, 10 May 2007 09:14:49 -0400
>
> I started the engine turned on the a/c set to high and the highest fan
> speed. It ran for about 2 seconds then the fans cut off.  Upon further
> inspection the fan switch test okay and when checking the other fuses
> behind the panel in the rear left cabinet I found that the 50 amp fuse
> was blown and the pressure switch on the high side below the service
> valve was burnt up.

I would check very carefully for a wire that got pinched or crushed
during installation, and any possible mis-wiring that happened on
installation.  It really sounds like there was a dead short to ground
somewhere in the A/C wiring.

If the pressure switch is fed from +12 V, you might look for a short to
ground after the pressure switch - or possibly the swich shorted
internally, in which case replacing the switch will probably fix it.
If it's a switch to ground, look for a short to +12 V before the switch.

It might be helpful to make up a jumper wire with a fuse holder near one
end.  Put a 20 A or 30 A fuse in the holder and connect that end to the
battery, then use the other end to power different parts of the A/C
system as installed.  You might also have to jumper around pressure
switches to get the system to behave as if it was actually running.
This way, you can blow up cheap fuses and pieces of wires while tracking
it down, instead of expensive fuses and pressure switches.

Matt Roberds