Ac come on only on max and works intermittently. Auto switch does not go off when pressed and ambient light blinks as the ac goes on and off.

SOURCE: the AC switch indicator light

go to this web site, it may help with the blinking, mine does it to, i have an 05 GV, http://www.suzuki-forums.com/1g-2001-2006-xl-7/13420-c-button-flashes.html

SOURCE: AC STOPPED BLOWING COLD; ONLY BLOWS ON MAX MANUAL SETTING

Your AC is low on refrigerant; The AC compressor needs a minimum amount of regrigerant to run. If and when it does run (while low on refrigerant) the air coming out of the vents will not be cold. The refrigerant you require is R-134A and is available over the counter but if you are the least bit unsure as to how to add refrigerant, taking it to a garage that does AC recharging would be your best play. If you want to try to add refrigerant on your own you will need the following, 1LB can of R-134A, an AC hose adapter to deliver the refrigerant, and preferably an AC pressure guage to ensure you are not overfilling the AC line which will damage the system.

SOURCE: AC & Rear wiper switch button indicator lights blink

The procedure for re-setting the HVAC control panel on a 1998 Dodge Grand Caravan follows:
With ignition on but not running
1. turn knob to air vents
2. turn fan knob to ON
3. temperature setting on COLD (2X) {I have dual temp controls}
4. hold top(rear wiper) and bottom (rear wiper with wash) buttons pressing down together until all the buttons cycle through (this will require 1 to 2 minutes of continuous pressing)
I learned this from a very helpful local Dodge service adviser

SOURCE: my 1995 toyota camry ac light starts blinking and

AC blinking is the self diagnostic system of the AC unit. A pro needs to repair this.

SOURCE: ac system goes to the defrost vent when on max ac

Heater ducting is designed to fail in defrost mode. Look for lose or leaking vacuum hoses. The you investigate the controls, then the heater / A/C box...