My 2001 PT Crusier will not crank over. It has a new battery, lights work,horn etc but will not crank over. It does the same thing when you try to jump start it.

Marco, check under the hood in the fuse box for the starter relay. You may be able to swap it with one like it if it has the same numbers on it just to see if it cranks over.

make sure the battery is charging, make sure the alternator is putting out correct amp/volts, check cable connections of battery - at both ends, check connections of harness at back side of fuse boxes, check harness connection block at firewall (both sides of firewall)
, check harness connections leading up into underside of dash.
Ensure all ground connections are tight and not broken.

You will need multimeter and probe tool with light.

if the motor does not crank and the dash lights come and other lights . check the starter or starter relay

Your not diagnosing the check light issue?

Have GM fix problem on lights. It's a common problem as is the transmission pin breaking. GM knows it but we have to pay??? Bad bad bad?....

Your alternator might be bad. Check if your alternator is functioning well.

EITHER HORN BUTTON STUCK OR HORN RELAY STUCK.REPLACE HORN RELAY FIRST ITS CHEAPER SEE WHAT HAPPENS.IF HORN PAD IS THE PROBLEM.YOU MORE LIKELY HAVE TO REPLACE WHOLE AIRBAG UNIT IF HORN PAD BUILT INTO AIRBAG IN THE STEERING WHEEL..LET GARAGE FIX.DONT ATTEMPT TO FIX AIRBAGS IS DANGEROUS LET GARAGE FIX IF YOUR HORN PAD BUILT IN AIRBAG.

you should push on your horn switch and if it makes a click sound then it usually means you need a whole new horn. it wouldnt help to get a wiring diagram and test some wires to see if you have power and ground going to your relay and horn.

find the horn ,it should be at the front possibly behind the bumper ,run a wire direct to it and see it works ,if it does work then its the wiring in the steering wheel ,but as this vehicle no doubt has an air bag then entrust this job to a garage because if you get it wrong the air bag will explode ,expensive job to say the least

The motor is gone and the switch could be gone too.

I would replace both to be on the safe side.
The switch is not that expensive. The motor is more expensve.