1995 geo tracker won't start. I've replaced everything except the ignition switch. It used to click when i turn the key, now it won't even click.

lock smith time. seems.
on some trackers there is lever there to unlock the lock
its so you dont turn off the key driving,
and then Air bags go dead and then get the maker gets sued
for that like GM just DID.
and that too can fail, as in all things made by man.

Can replace ignition switch w/used unit for around $100

Check connection battery,could be starter.

You would need to use a meter or test light to find out if you have power going thru the headlight switch and thru the dimmer switch.

first have the battery load tested as it indicates that there is a dead cell
If there is a dead cell then the dead battery will consume most of the power from the jumper so there may not be enough left for the starter and the ignition
to check for a power drain , install an amp meter i the battery to ground wire and see what current draw is occurring when everything is turned off
up to 1/2 amp indicates that the ECM is using power for the memory
up to 2 amps indicate a light on--glove box, boot , interior radio etc
more indicates a problem relay

If you changed the ignition switch make sure the new one's locking pin is working right. Or just change the ignition switch. new switch new keys.

Ignition Switch!!!

Check the ignition switch steering in column, it goes bad also over time, you cant fix or rebuilt it and its expensive unit, will have to buy a new unit or one from a junk yard, assuming the battery has a good charge and new starter. try to play with the ignition switch by turning the key back and forth many times and see if you get some kind of contact to the dash light or starter while everything is connected.

check starter relay

Even though the lights work, the battery may still be just short on power to turn the motor over thus the clicking. Try charging the battery or jumping, if you still get a clicking it would be the starter solenoid. Considering the year you may just want to replace the whole starter.