1995 J30 AC blows hard for 10 minutes then barely blows.. :(

[CustomJ30]

My 1995 J30 has cold AC. The problem is that after 10 minutes of driving it, it barely blows any air. If I put my hand toward the vents, they are very cold, but the thing just will not blow hard. If I increase the fan speed, it will speed up, then just slow back down to almost nothing. What could be the culprit?

[coolyun_98]

Hi:

Use your factory service manual and initiate a HVAC automatic cheack. Tell us what you find out.