Symptoms: Turn key car starts dash lights do not light though. Release key engine cuts off abruply. Mechanic says pretty good chance it's the ignition switch. But, how do I know which part to replace? I take notice that I can get the switch (called a steering switch). Or a key lock cylinder (part key is inserted into). Or the whole lock/switch assemly (the most expensive option).
Any advice or help would be greatly appreciated.

 

I would replace the lock cylinder first since you know its bad. Then see how it goes.. but it sounds like they are both bad.