Check the A/C fuse, that's what happened on my '85.
for the fleetwood Brogham it is located on the right fender next to the receiver dryer. there is a black cover over the fuse block. on the Fleetwood FWD is located under the hood in the center top of the fire wall. there are two separate box's. a left and right one.
HCAC fuse should be under the hood
check the fuse or the ground on the heater
Facing car, on left side, back behind fuse box. Should be blue.
Usually in or near the fuse block by steering column
blown fuse
short circuit in the circuit
In the 1967 Cadillac Fleetwood, the circuit breaker is typically located in the fuse box under the dashboard or in the engine compartment. It may vary based on the specific model and trim of the vehicle. It is recommended to consult the owner's manual for the exact location.
THE Exhaust manifold is near the firewall maybe that's is, a fuse box is under there to might want to check it.
You could go to any local Auto Parts store and get a Chilton Repair Manual for that specific make and model.
The fuse panel is located under the instrument panel (dash) on the drivers side,mounted on the firewall in the left corner. Doc J