Blower Motor/ AC compressor clutch switch question

[Valina]

Hello 

Currently working on 1971 ss454 Monte Carlo 

The issue is AC clutch not engaged with controls in any of the 3 AC positions.

All relays and wiring to be best of my knowledge has been checked. The switch outside of heater AC control box shows 8-9 volts this goes to the AC compressor. I believe the blower motor is taking up too much power for it to engage. If anyone has seen this issue and repaired it please contact me via cell phone 414-350-4622. My names Dan any further information will be greatly appreciated going forward. Enjoy the rest of your day!

[Dtret]

Silly question but is the system properly charged?

[GRAY 70 Monte Carlo]

Looking at the wiring diagram it shows that the circuit comes from the to main switch to the thermal switch then to compressor the blower mother is on another circuit coming off the relay. I would get a voltage reading from the at the thermal switch on both sides of the plug and check to make sure you have the same voltage on both sides  with it pluged into the thermal switch and car running and A/C on . Then check power at compressor. I have not had this problem myself but reading the wiring diagram I would think either main switch or the thermal switch. The thermal switch cuts power to a/c compressor in the case of freeze up and protects compressor. I hope this helps you good luck 

[Valina]

Hello,

Thank you for your feedback. So I charged the system by adding a switch at the anti diesel relay. At that time the system recovered, vacuumed and then with the vehicle back up a running charged with R-12. The system was performing well. As I type this response this vehicle has a different wiring harness or option’s based upon what I’m looking at in the chassis manual picture. Instead of the tan wire coming from the control switch to the thermal switch on the evaporator housing. In conclusion the light blue wire that is at my thermal switch came from the blocking relay. Going back over this issue is quite time consuming and educational at the same time. It turns to be the blocking relay was bad. Thank you very much for your assistance with this issue. The picture wasn’t the greatest but it does show the difference in wiring identity.