I posted about the blower being inoperative on high setting only in our '76 Salon (w/ standard heat and A/C) some months ago, and I never resolved that problem.

Well, I'm going to revisit this problem because now wit won't work at any speed except the ambient "flow-through ventilation" feature which operates as soon as the ignition switch is turned on (oh, goody --- just in time for winter; yay).

I replaced the relay within the last six months, but was unable to scare-up a new blower switch or resistor (at least none that fits correctly and actually covers the big hole beneath it in the blower housing).

All fuses are good, including that little inline 30A bugger in the orange wire out under the hood. Power from that wire goes into the new(ish) relay, but it doesn't come out. Power is reaching the resistor via the brown wire at all times that the ignition switch is on. Is the switch supposed send a second signal to the relay or resistor when any of the HVAC functions are engaged? 'Cause that ain't happenin' . . .

Beyond these tests I'm having a bit of trouble interpreting the troubleshooting chart in the factory service manual; I'm not sure where some of the components mentioned are located. Can anyone point me in the right direction to diagnose this problem . . ?

It will probably be so obvious that I'll feel like an idiot . . . but I'd rather feel warm than intelligent.

Jeff