1995 5.7L Chev Sub LT front HVAC doesn't operate

[Stauntonian]

The front HVAC controls have stopped working entirely. The blower stopped functioning one morning commute to work when operating heat and blower on highest settings. I turned blower switch off for fifteen minutes then turned blower switch on and full operation returned. That evening trip home the blower functioned very well, A/C, too. The next day no front controls would operate and haven't since. The rear heat works. Main fuse 12 tests good, and looks new. Your assistance is appreciated to help me troubleshoot and resolve this problem.

[Eggert]

Hi,
it is time to do basic wire tracing.
Do you get 12V at the blower motor?
Does it run if you put 12V on it?
Take the blower out of the box and see, if it is frozen.
This should point you either to the blower, the control, or a bad connection.
Take care, Eggert

[Stauntonian]

Thanks for your reply Eggert. The voltage at the blower with engine running is below .5 volt to zero. The fuse circuit voltage is 15v. The blower runs w/ 12v applied.

[Eggert]

Great.
So now we know that the problem is between the fuse and the blower, may be the control module or a bad connection. Now you may want to trace from the fuse to before the control module and also from after the control module to the blower. The high speed setting will bypass the resistor pack, so use this first. This should narrow down the problem spot.
Take care, Eggert