Cruise Control Help!

2000 Chevy Suburban. No cruise control. 

I have tested the inputs to the cruise module as stated below. 

A: Cruise on from stem switch. On = 12V 
B: Speed set from stem switch. SET = 12V
C: Resume/Acc from stem switch. RSM = 12V
D: Brake/Clutch circuit integrity. Key on = 12V
Apply brake or clutch and circuit goes low = 0V
E: Ground (Black/White)
F: CC Module power. Key on = 12V
G: Stop lamp switch feed. Brake applied = 12V
K: VSS input voltage. AC voltage generated by VSS.

When I get to K, I am reading 12 volts between K and E at stop. With the vehicle in gear and rolling, it drops to about 6. Checking the frequency, I get .6 in rolling or stopped. 

The speedometer works. Checking live data on the OBD2, the VSS is outputting correctly and reads accurately. 

Using the parts shotgun, I have replaced the stop light switch and swapped out the cruise module for a used one. No luck.

What is my next step? I'm assuming the output to the cruise from the VSS has failed somewhere. Is that a output from the ECU? If so how do I test that?

Is there a secondary switch on brake pedal for the cruise? My Infiniti has 2, one for the cruise. the little rubber bushing on brake lever fell out and caused mine to stop working 

In reply to Subscriber-unavailabile :

There is a switch on the pedal. I have tested and replaced it. That circuit is doing what it is supposed to. 

Bump for the Sunday crowd. 

In reply to Toyman01 :

The Cruise in my Civic did not work for a year. I finally realized there are 2 sets of contacts in the brake switch. if you barely tap it, the cruise is disengaged. If you press a bit more it will light the brakes lights. the fist position was always engaged.

In reply to Mark L :

The pedal switch on the Suburban has three contacts. They are all working properly. 

I'm starting to think the output from the ECU has puked or there is a short in the harness somewhere. 

Bumping this one again for the weekday crowd.