Date:         Wed, 12 Aug 2015 01:21:46 -0700
Reply-To:     vw_van_fan_Mark <madvws@COX.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         vw_van_fan_Mark <madvws@COX.NET>
Subject:      Re: A/C fan and burning smell
Comments: To: Dick Wong <sailingfc@DSLEXTREME.COM>
In-Reply-To:  <3i3R1r00W08X5Fr01i3Sct>
Content-Type: text/plain; charset=UTF-8; format=flowed

The front controls connector is unlikely to burn out at the 'speed 3'
pin since speed 3 uses a relay back at the A/C unit. The pin only
carries a small current to trigger the relay and the heavy load is done
in that relay. I would replace the relay that handles fan speed 3. There
is another relay for speed 4. So the connector pin for speed 4 is also
only a low current signal and again would be unlikely to burn out.

The fan speed 3 relay function is built into the main A/C relay so
replacing it means getting the special A/C relay. Speed 4 uses a very
common generic relay type.

The burning smell is obviously worrisome. The rear A/C wiring is pretty
notorious for melting and you may have to look pretty closely to see it.
But since most of the wiring is inside the side panel with the relays
and not in the fan airflow the fan shouldn't so easily pick it up unless
there is a lot of it. The other possibility is that the smell problem is
with one of the 2 fans or one of the 2 fan resistors. There is a pair of
fuses in the rear wiring near the relays and each fan has one. You could
try removing the two fuses one at a time to make sure both fans are
actually turning and listen that they both sound the same on the same
speed settings. The 2 resistors get hot and each is cooled by their
corresponding fan. If a fan goes bad the resistor will eventually cook.
The resistor isn't used on fan speed 4 so maybe not related to the smell
in your case but I think it still might be. Please do try pulling the 2
fuses to make sure both fans are operating the same.


Mark

Dick Wong wrote:
> Looks like I need to drop the front plenum. I couldn't pull out enough wire to get to see the connector.
>
> I tested the switch with an multi-meter and I seem to get continuity in the terminals with varying resistance, it seems okay.  When plug it back in, I do not get any fan at the "3" setting.  What else can I check?
>
> Thanks.
>
> -Dick-
>