Depending on what engine is in the vehicle, it may not have a distributor. If the engine is the 5.7L it does have a distributor. If you have the 4.8L or the 5.3L these engines do not have distributors.
Short to ground or overloaded circuit
That is possible.
worn ignition switch
Yes it can cause bulbs to blow.
Check Antifreeze level..make sure there are no leaks under the vehicle.
Probably a short in the horn wire.
Have you checked the heater core? It's happened to me before.
It could be that you need coolant or it's low.
Either a faulty thermostat or you have a low coolant level.
computer fuse blow out when turn ighition on what is the cause
An Electrical Short Cut somewhere would cause it to blow the fuse. A pinch wire would ground the system, and cause a shortcut.
Defective blower motor Resistor Pack. Replace it.