I think the following change in i.atcorr('s descriptive message of the sunaz string,) is required:
grass70/imagery/i.landsat.toar $ svn diff
Index: main.c
--- main.c (revision 62829)
+++ main.c (working copy)
@@ -209,7 +209,7 @@
_("Date"),
_("Sun Elevation"),
_("Sensor"),
- _("Bands count"), _("Sun Zenith Angle"), _("Time"));
+ _("Bands count"), _("Sun Azimuth Angle"), _("Time"));
lsatmet->descriptions = desc;
lsatmet->guisection = _("Settings");
Nikos