Need help - FB ac controls not lighting up
 

Anyone ever have there ac controls on the 84-85's no light up? I can push all the buttons and still nothing. the fan switch and temp works and the AC will come on once it is engerized manually.

I have checked all the fuses and tried a search. I am sure someone else has nad this problem.
Thanks

Hope this helps, it is what I was able to find,



Its possible the Logicon (or Rogicon,as the Mazda book puts it,heh,heh..) is bad.
They are very prone to failure in the 2nd gens,and Ive heard the 84-85 cars with electronic controls are known to fail too.First check the fuses.There is a 15AMP fuse under the dash that feeds the control box and a 20AMP fuse for the blower motor.If they are both good,youll have to dig into the dashoard for an answer.I have seen 84-85 logicons on Ebay for about 75 bucks,so they are obtainible if yours is toast.It could just be a loose or corroded plug.
The vents on the 84-85 cars are a little odd.They dont all flow the same air and some are unable to distribute hot or cold air at all,depending on the switch positions.Heres the info straight from the FSM......

For Rogicon(heh,heh) style cars(GSL/GSL-SE).....
VENT......heater core bypassed....center,crotch and side vents flow cold air.

BI-LEVEL.....heater core in split flow.....center,crotch and side vents flow cold air....defrost,floor and side defrost vents flow hot air.

HEAT......heater core in full flow......floor,defrost and side defrost vents flow hot air.

DEFROST......heater core in full flow.....defrost and side defrost vents flow hot air.

I believe the AC system is after the blower,but before any of the diverter doors in the dashboard.Thus,you can send conditioned air to any of the vents you choose.Air conditioned air doesnt always mean cold,just dry. Air conditioning with the heat on is actually very pleasent in the winter or on a cool,humid night.The setup of our vents allows you to mix it up between hot and cold air,even if its been dried by the A/C previously.

But, you are limited in what vents you can deliver hot or cold air to.The crotch,center and side vents are for cold air only.The defrost vents are for hot air only,unless you turn down the red/blue heat dial,and your heater control valve actually works.

The levers on the side vents are for outside,force fed air.In the fan position,they are plumbed into the blower venting.In the wavey postion,they are plumbed around the blower,directly to the outside air vent at the base of the windsheild.Airflow is determined by vehicle speed.[Thanks to steve84GS TII]

...I had no idea of any of that. Thanks for passing along the info.

This also explains why it takes so damn long to heat up the car when I usually set it for "vent" or "Bi-level."

Yep, not a problem.