HELP! AC Fan speed question on '73

[mhicks]

I have found that the AC fan speed has a different wiring that the newer trucks (74-87) Does anyone have a wiring diagram of this setup? I do not have the MAX speed on my fan. I have checked all of the resistors under the hood and they are OK. All of my fan speeds work with the fan speed switch. When the temp control is moved to about a 1/2 inch from the left and the control is in the AC position all of the speeds work. Now, when I move the temp control all the way to the left I think it is supposed to kick the fan on HI HI. When the temp control is all the way to the left my fan speen switch no longer controls the fan speed. I think that the temp control is supposed to kick the fan in to MAX and the speed should increase signicantly. Does anyone have a '73 that can verify this for me? How about a wiring diagram for that year model. I have noticed that LMC does not sell the AC/Heater control panel for the '73 but do for the others. Any pointers?

[gchemist]

Replace the motor relay located on the A/C box. The relay contols the highest fan speed seperately from the lower settings. The relay costs less than $10 at the parts store.