Range rover have no heat or ac

One thing you can check is relays # 6 and # 7 for the blower motors in the engine compartment fuse box. The p38s are known for corrosive vapors from the battery melting these relays. At best you'll just have to replace the relays if that don't work you might have to replace the fuse box. Good luck

First thing I would do is check your fuses. If all of your fuses are intact, I would make the assumption that it must be the control assembly itself (your actual dash control unit) since to my knowledge it is the only point where the two exclusive systems (heating and AC) are integrated with each other, aside from sharing the duct and to some extent, the electrical system. Being that neither the heating NOR cooling system will work, it seems the only common denominator.

If you have blown fuse(s), remember that fuses almost never blow for no reason (wierd things DO happen on occasion!), and this is usually just a symptom of a deeper issue, such as a short or fault in your electrical system such as your fans, or other components, drawing too much current. Locked fan rotors will blow fuses, for example. Having to replace the fuse again in short order would indeed indicate the need to troubleshoot further.

Good luck!