Exactly like mine – no heated air at all.
The original metal vacuum valve on the bulkhead behind the engine fell apart due to rust, I fitted a modern plastic one which has given no trouble whatsoever. Check yours first – suck hard on a pipe connected to it and listen for noises as it opens and closes.
if it’s ok the problem probably is in the rotary gubbins ahead of the gear selector, behind/below the radio. It has a number of cams which rotate on a shaft to drive all the things which need to be driven to put the climate control system where you want it. You can see part it if you remove the rhs footwell panel.
Be sure you know exactly what to do before you touch this.
Refer Kirby Palm’s fantastic book “Experience in a Book” – 730 pages of experience, knowledge and tips on XJS.