98 GMC Jimmy Air Conditioning Problem

Hello... I have a 98 GMC Jimmy. My problem is the air conditioning light blinks when you press the button, but it doesn't stay on. Sometimes the air conditioning will just come on as I'm driving down the road, but it usually just won't come on when I press the A/C button. Can you help??? Thank you!

Automatic or manual controls.
If automatic it may need rebooted.
Has the battery been dead or changed?
Does it have gas in it?
On the automatic ac control set up a good engine/ac capable scanner will read out codes and point to the problem.
If you got codes post back codes.
MT

It's automatic climate control, battery was replaced in the winter, so I don't know if the A/C worked after that or not. Yup, full of gas. I haven't had it in anywhere to have it hooked up, so I have no codes. I don't know what rebooting means. Thanks for any help!!!!!

It's automatic climate control, battery was replaced in the winter, so I don't know if the A/C worked after that or not. Yup, full of gas. I haven't had it in anywhere to have it hooked up, so I have no codes. I don't know what rebooting means. Thanks for any help!!!!!

To reboot it.
With ign off.
Pull the fuses or disconnect the neg battery cabel and then hook it back up.

Had to laugh - does the compressor have 134A in it as the coolant gas.
Set the auto controls to full cold and not a temp to test as sometimes those auto poitions confuse the compressor as the contacts get deposits on them.
Common for Blazers is by 80-100k the seal in the compressor leaks, the connectors get loose pins and bad contacts, or the low pressure switch goes. Most AC shops wil test and give an estimate for free or a low charge before doing any major work so ask when you schedule an appointment. If you need a compressor get a NEW not rebuilt as cost diff is small and rebuilts never last.