what does the ignition switch control in a car, if it stops working what problems does it cause?

Answer 1

The switch is used to switch battery power to all those electrically operated things that make a car start and run with accessories included ~~

Answer 2

It turns on a set of relays - electronically powered switches - that turn on almost all the remaining electronics in the car, including the ignition system, engine control module, starter, radio, just about everything. If only certain parts of the car don't work, check the relays and fuses as well. But it could be the ignition switch - I've seen these fail part way. The windshield wipers (and many of the accessories) on one car I owned would stop working if you jiggled the keys wrong, and wiggling the key could turn them back on.

Answer 3

When key is turned to START:

If the lights do not dim at all as key is turned, then no power is getting to the starter. Cables/connections are dirty, loose, disconnected, frayed or broken.
If the lights dim to nothing as key is turned, battery is low, and/or the cables are in poor condition, or the starter has excessively high internal resistance.

If lights dim only slightly as key is turned, then starter is defective or worn (if it's turning very slowly).
By the way, it's normal for the lights to dim slightly as the starter operates. If the starter sounds like it's otherwise working normally, then you can disregard slight dimming of the lights.

You can check the starter's internal resistance with an inductive ammeter. Any more than a couple of hundred amps means starter motor trouble.

A "click" or "click-click-click" means the solenoid is trying to grab and hold, but it can't. If it can't, the motor can't turn, since it gets its current through the connected solenoid. A solenoid that won't grab is either defective or the battery is too discharged to allow it to grab.

It's easy and cheap to disconnect the battery ground cable and the live feed to the starter, and clean all the connections back to bright metal. Don't forget the engine-to-chassis ground cable! If this gets broken, it can cause starting electrical problems in itself.

Answer 4

If the start contacts fail, you'd have a no crank condition. If the on contacts (run position) fail, you'd have a no start condition. Many times the switch contacts may be intermittent which is more difficult to analyze. See if there's any service bulletins about your ignition switch failing
http://www.edmunds.com/maintenance/MaintenanceServlet
http://www.mycarstats.com/
http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm

Answer 5

I dont really have an answer but I also have a question. I have a 99 Oldsmobile Aurora and my switch went bad but when I got it replaced the windshield wipers stopped working, the radio doesn't come on, the ac/heat stopped working, my tachometers stopped working, the information doesn't come on, and my anti-lock abs light came on, and my windows dont roll down. Any advice to this?

Answer 6

easier to say whats wrong with car and see if ignition switch would cause it.

so many sytems tied in with switch usage would need more info.

a bad switch can cause anything from a complete no operation of vehicle, to dash lights not working, to warning buzzing constantly on to the starter continuosly running, to.....so many things.....

Answer 7

you're gas could be frozen, therefore the fuel pump wont work. Try using gas line antifreeze

Answer 8

EVERYTHING.............................

TRY FINDING AN INDEPENDENT SHOP INSTEAD OF THE DEALER OR A CHAIN STORE BECAUSE YOU WILL BE OVERALL MORE PLEASED WITH THE FINDINGS AND THE SERVICE.