90 cherokee wont start
 

I've replaced my starter and starter relay, all I'm getting is a click when I turn the key. Any suggestions on what to do next?

This may be an obvious answer but you checked the battery right?

After checking the battery, as mentioned....

Check the battery ground cable, and engine ground cable, for looseness, corrosion, and corrosion in the crimp where the wire goes into the connection lugs.

Check the battery Positive cable that goes from the battery to the starter, for the same conditions mentioned for the ground cable.

Checked the battery cables after putting in a higher output battery. None are corroded or brittle. Just replaced the flywheel position sensor and still nothing.

You checked the battery cables, but how about the engine ground cable?
Does your negative battery cable go directly to the engine? There should also be a ground strap between the engine and the body.

Is the click you hear, coming from the solenoid on the starter?

If so, make sure there is 12 volts present at the large positive wire on the starter, at the bolt on the starter.

Ground cable is good.. can't quite tell where the click is coming from
Also, is there an obd port?

it could be a bad computer. I had a similar issue. A new computer solved it.

Try starting in neutral. Could be your neutral safety switch.

I've had battery cables that looked good until I cut them open and were corroded inside.

Replaced the computer less than a year ago.
I can hear the neural safety switch click, and I've tried starting in neutral. I wish it were a manual so I could try a push start. I'll have to try cutting the cables open to see if they're bad inside.