Date: Tue, 15 May 2007 23:55:35 -0400
Reply-To: Kim Brennan <kimbrennan@MAC.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Kim Brennan <kimbrennan@MAC.COM>
Subject: Re: update on a/c fuse blowing
In-Reply-To: <8C9652BCCD068C3-1ADC-1A62@FWM-R15.sysops.aol.com>
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Most of the wiring for the AC goes up around the drivers side D
pillar. In other words, behind the cabinet at the rear of the westy.
But you don't need to pull the cabinet. Just the shelves and the
corner section in the cabinet.
This is where the relays, and fuse and connectors are.
The cables to the fans go up from that point.
The cables to the engine (and freon lines) go down from that point.
Check the connectors. If they aren't white, but instead are brownish,
then you have a resistance problem in your connectors. Not too
surprising in a vehicle 17 years old. You can try using a small file
to clean the oxidation off the connectors, or you can have someone
put new connectors on (cutting back the wiring to good copper.) Be
aware, that your copper wiring has probably oxidized as well.
Oxidized connectors and copper wire increases the resistance of the
wire (causing heat, which is what the browning is caused by). If
there is enough resistance, bad things can happen.
Blown fuses are usually caused by LACK of resistance. In other words
run away voltage going to ground.
Check the speed fan switch itself (it's easy to get to on the dash).
Probably not your problem.
The fans work by having a resistor throttle the current. The more
resistance, the slower the speed of the fan. the less resistance, the
faster the fan. Since you have problems with speeds 3 and 4, one or
other of the AC fans' resistor packs could have a dead short. There
are two fans up there with the evaporator. Each has it's own resistor
pack.
The way to check is with the power off, check resistance on the hot
line going to the fans, in each of the speed switch settings.
Resistance you are measuring is to GROUND. It should vary, at each of
the 4 speed settings, with speed 4 having no connection to ground. If
speed 3 or 4 show 0 or a very small ohm value (less than 500 ohms)
compared to ground, this is likely where your short is.
I'm not positive but you may be able to disconnect each fan
separately from the wiring behind the cabinet and check each
independently.
On May 15, 2007, at 1:15 PM, David Clarkson wrote:
> We are still trying to track down the problem blowing the 50 amp
> fuse with the 90 Westy a/c. We have fed power just to the fans and
> on 3 or 4 speed it blows a 30 amp test breaker. I really dread
> pulling down the housing for the evaporator to check for a bad wire
> but it seems to be inevitable. The fans run smoothly on 1 and 2
> speed and originally ran for about 5
