Two things maybe wrong"
1. Was it raining hard that day? The outside vents suck in air unless you use the inside vents. If there's little air from the outside then the a/c light blinks indicating you need to switch to inside vents. This also happens when the air is humid after a rain storm.
2. The blinking light indicates your A/C refrigerant is running low. Fill it up with R-134a.
I think it was problem #1
Bookmarks