Heater display died
On my 88 I had a similar problem. My display would blink on and off then it would go into this mode where the display couldn't be made out at all. After tapping a few times it would go back to normal. Someone on the forum told me to take the 2 clips in the front off and pull the head unit away from the circuit board. Look at the connectors on the circuit board and clean them with an eraser until they are shiny and then put it back together. I believe there is a more detailed instruction on this on the tech tips under c4 section called intermitten ac control unit. I did all of this and it solved my problem. Might want to try this if you haven't already before buying another.





