Ignition troubles I have a 1996 jetta 2.0. Car has been sitting for a couple of months. Went to start the car and starter would not activate. Jump solenoid on stater. Engined turned over. Found crack in ignition coil. Replaced coil. checked volts to ignition switch. getting 12 volts to ignition switch, but non to to starter. Checked grounds under battery, and to engine. Olmed out ground from under battery to fuse box. grounds good. when key is turn to run. throttle body activates, then all lights and instrument panel loses power. Checked anti theft unit. What i can see its deactivating. No indicator on instrument panel but theres a light flashing inside of a after market radio. How can you tell if its the alarm or the ignition switch.

If everything else works when you turn the ignition switch "on", but the starter will not engage, it could be one of three things:
1) Ignition switch is defective
2) Starter is defective
3) If it is an automatic, the starter interlock may be faulty.

The best way to check the starter is to remove it for testing. Remove the starter (3 bolts) and take it to your local auto parts store for testing. Be careful and support the engine from below with jack stands as one of the starter mounting bolts is also an engine mounting bolt.

If the starter tests OK, then it may be option 2 or 3 (above). If the car is an automatic, try cranking it in "N". This will tell you if there is any sort of starter interlock problem. If this fails, or if the car is not automatic, then the ignition switch is most likely the culprit.

I hope that this information helps!

It might be your anti-theft alarm system. When the car doesn't start, is there a ticking sound inside the car? If so, hit the unlock button a few times on your keyless entry remote, until the ticking stops, then try to start the car. Hopefully this helps.

If you car has an alarm try depressing the Valet switch and de-activate the alarm. What happens with car alarms is they are auto activated when the battery is dead and re-connected. Also go to the starter itself and find the solenoid. There are usually one or 2 single wires attached to the rear of the soleniod. One is an ignition bypass and the other is 12VDC from the start switch. Have someone turn the key and check for 12VDC on the wires. Only one of them will have voltrage when the key is turned to start. If you have 12DC on the wire terminal with the key turned to start then you have a bad starter / start soleniod.

have the key in the on position when you hook up the battery

I had the same problem My ignition went out key turns everything turned on but car would not start. replaced ignition started right up then 2 months later did it again replaced a part that is on the firewall can't remember the name of the part but it is something modular. call the dealer they will tell what what that part is. car has been running great since

replace power wire from batt to starter

sounds like you have a problem with either the ignition switch itself or the solenoid on the starter if you jump positive power to the small wire on your starter and it turns the starter then it would be your ignition switch if it does not turn it replace your starter

Check the alternator.

is the trigger wire on starter (sm conn) energised when you turn key? should be close to 12v. could be bad ign switch if no power..

the same thing happened to my 1996 jetta trek.

when the alarm went off on me and the car would not start i walked around to the passenger door, locked and unlocked it, therefore the alarm went off.

but the alarm only went off if the car battery was low and had trouble starting.