Badassxj

On my 96 xj this box all of a sudden is flashing and when is does my jeep won't start. If i jiggle the wires on that box it starts. What is it? It's a plug maybe for engine light tester.

Crash_Course

Does your jeep have any aftermarket security system equipment on it? As they age, these systems start to flake out and if it includes an ignition disable option, can cause a no start.

I bring this up because that kinda looks like one of those plugs that an additional electronic key would plug into. ( I think they just had a circuit with a given value of resistor on it). Something similar used to come on 90's GM trucks.

I have a '96 also, and while there's a lot of crap up under my dash, there's definitely nothing that lights up, and that plug doesn't look like an OBD2 port.

Bustedback

Those were a dealer installed anti-theft device from the 90's. All it does is interrupt the start circuit until you put the "special" key in it to complete the circuit.

Badassxj

How do I disable it? Do I have to take it to the dealer? Because I don't have the key.

Crash_Course

It's most likely a plug in add-on module... trace the wires and see if anything plugs inline in the normal harness, where if you removed it, the wiring would just plug back together normally minus the added component(s)

Bustedback

Look for yellow butt connectors by the steering column.