At 03:10 PM 2/16/2012, Derek Drew wrote:
>Only about 1/4 of the heat exchanger is actually getting air because
>of this bafffle, which has holes in it, mostly along one side.

Here's a WAG for you: could it be sending air preferentially to the
hot side of the heat exchanger?  Or could it be directing flow so
that it tends to travel diagonally through the heat exchanger,
increasing the dwell time in the core?  I don't have a core to look
at so I don't know whether either one of these even makes sense.

It may just be to limit the volume, to increase output temp at the
expense of flow.  You'll notice that the manual and dash markings
specify blower speed 2 for maximum defrost effort.  It's not clear to
me whether it's dwell time in the core or on the windshield that
they're optimizing, but clearly it's something.

Yours,
David