Destination monitor
From Tardis Wiki, the free Doctor Who reference
The Eighth Doctor's TARDIS had a destination monitor, which gave details on where the TARDIS landed. (AUDIO: Island of the Fendahl)
After Charlotte Pollard spilled ginger pop all over the TARDIS console, the destination monitor was on the fritz. As a result, the Doctor and Charley arrived earlier on in French history than intended. (AUDIO: The Mummy Speaks!)