airbag lite on, heater fan will not come on?

[davidt753]

I have 99f350 which we bought new has been trouble free until this year,but now that it"s turning cold a new problem has appeared,about 1 month ago I replaced blend door actuator, it solved the problem I was having,2 weeks ago we had our first overnite low below 45 and problem appeared. When you first crank truck airbag lite stays on and heater fan will not come on any speed,everything else appears to work,after about 20 minutes fan comes on and lite goes out. All help appreciated. Thanks