'98 K1500 Suburban

Been having trouble with the AC this summer. After a long list of checks, I've found that the problem is that the AC request signal is not consisting reaching the PCM (pin C25). I don't have a good AC wiring diagram at home, and won't be able to get by the library on Monday -- assuming the wiring diagram will even show what I want. Obviously, the AC request circuit originates in the dash controls. Before I start taking the dash apart, does anyone here perchance know if there are any connectors or components between the dash controls and the PCM where I could further check the circuit?