It starts with the switch fine but when i let go of the key it cuts off

Wiring diagram is in the parts list, a no fee download from the Husqvarna web site. See following URL

https://www.husqvarna.com/us/search-results/?groups=DOCUMENTS&q=Yt46ls

The start solenoid control side winding has two conductors, WHT and BLK. BLK is the return to battery negative. WHT is fed fused battery positive from the ignition switch through the PTO switch thru Brake switch.

Suggest you use the volt meter referenced directly to the battery negative post or clamp. Probe the ignition switch "S" contact WHT wire. With switch in START position the S contact must be battery positive which in turn means the WHT wire must be batt pos. Then follow the WHT wires to/thru the PTO switch, to/thru Brake switch, to solenoid.

Comment for further assistance.

Could be several things. Battery connection, starter solenoid, starter, neutral safety switch, ignition switch. First have someone hit the starter while the key is in the start position. If no start, check to see if voltage is at the starter solenoid. Try moving the gear indicator back and forth from P to D with the key in crank position. Make sure the park brake is set. Make sure the battery cables are clean and tight. There should be several feed wires coming off the positive post. Make sure all are ok. Some are fusible links and may have burnt.

Time to change out your ignition switch. Sounds like the internals of the switch leading to the electrical or lever part of the switch to start or shut off is broken and all you get now is a key that will turn to the off position but will not engage correctly to turn the internals to cut power to the engine.

Neutral safety switch, try turn the key on neutral, jiggle the shifter, shift thru it's range, it may have come unplugged, or an alarm cut off relay or such.

sounds like an ignition switch problem sometimes key is making contact to start and not other times

I have a bike that at one time I'd be riding along, and the motor would die, and all lights and instrument go out, as if I turn it off with the key.

Turn key off, back on, and all would be fine until the next time.

It turned out to be a bad ignition switch.

tune up,fuel filter.

Can you hear the fuel pump come on when you turn the key on? First thing I would check is the fuel cut off switch located in the trunk on the driverside quarter panel.Sometimes this will cut off the fuel if the vehicle is jolted from a pot hole or collision. It's a little black box which may have either a red or black button on it.

Sounds like the keys are not cut right if you make a copy of a worn key thy will not work right go to dealership show them proof of ownership and vin# they will cut new ones for that ing switch

Saturn Ion's have a problem with the starter switch in the steering column. The security feature built into the key is a small resistor. When the key is inserted, the engine computer 'reads' the resistance and accepts the key as valid. The problem is that the pin that the key contacts is gummed up INSIDE the ignition switch. A new switch will fix the problem but Saturn won't cover the replacement though they have issued a tech bulltein on the problem.

The other fix that I did based on an Internet search is to cut the small 24 ga white wire coming from the ignition switch WHILE THE CAR IS RUNNING. The engine computer defaults to the run mode and will no longer look for the key verification. The small key symbol remains lit on the dash but the car starts everytime. Small price to pay. The real answer is that Saturn should replace or discount the repair due to HEAVY grease in the switch the gums up over time. Under 40 degrees, the connection is lost to the computer.

Deere-guy