Toyota Repair: A/C not cooling at idle, 22re, toyota truck

Question
I have a 1989 toyota truck (22RE) that is not cooling at idle. It works fine, very cool, at other speeds. I understand this is a a/c amplifier adjustment but I haven't seen this switch. ? Does this truck have an a/c amplifier?  Thanks for your help
Darryl  

Answer
Yes it has an amplifier but it is not adjustable like the earlier models from the '70s and early '80s, it's probably not the problem anyway. Has the sytem been checked to see if the freon pressures on both the high and low sides are correct?
If not, this is the first step, there may not be enough freon in the system to turn the compressor on at idle.