Vectra headlight/tail light & outside temp?

My 1999 Vauxhaul vecta GSI Showes on the Dashboard display, Headlight/Tail light Check. Also at the same time this problem appeared the outside temp display started showing exceedingly high readings (40C - 60C) All Lights are working fine, outside is definately not 40C (I can tell by the frost!!!) Any help/advise will be appreciated as I am at a loss.