Car clicks but wont start...power is good with interior/dash lights.....

dash gauges or warning lights?
any/either illuminated?
Never been a fan of removing cable for test, always relied on test equipment...
Do you have access to a volt meter?

the ecu controls the power to the pump and injectors. are you getting error on every test on reader that can be the ignition relay. its in the dash when you turn the key should hear it go click click. if just one click then one side of it has gone. there is the low volt side, ignition interior dash lights etc. high volts is ecu abs, air bags. etc. low volts go to the abs and ecu but when engine started it needs the high volts to be there to run.

you might have a short in your wiring and that can take a long time to see whats going on there.

OLder cars YEs you can jump it without a battery. But in newer cars that use computers and advanced Eltronic ignition/timing/ful injection you have to have power to the cars computer. without a good battery the car will not run.---------------------------------------------------------------------------------
Renault CAN Clip

and the mystery vehicle is?

Have you had you starter checked?

Your interior light are controlled by the dial left of the steering wheel. It is s vertical dial and a dimmer for your dash lighting but also will turn your interior lights on and off. Turn it vertically until it clicks off.

Hope you can read that? Check the fuses for those relays, the two on the right. Not only check the fuses, use a test lite to check for voltage on the fuse circuit. Check the four fuses on the left, also, some are hot all the time, some go hot with the key on.
The top two wires at relay is the load side. The bottom two wires are on the control side of relay. The control side needs voltage and ground. Your gem module controls ground. Sometimes when battery voltage is lost, some modules may need to be reprogrammed? I don't have that info. In my opinion, clicking is either intermittent voltage or ground. Right now I'm thinking ground, controlled by the gem model. I could be wrong?

try car to car boost-battery charger may not be working correctly or set on low amp charge -interior lights and dash may all light but battery may not be strong enough to energize starter have battery tested if battery good than check for power to the starter if power-- starter may be shot can remove also and have tested at most auto stores free if no power battery -wiring-or connection issue would need to test fuse panel-ignition switch and starter solenoid

the battery is dead, it's as simple as that. the battery only needs a tiny bit of power to turn on the interior lights and panel lights, but it does not have enough to dis-engage park lock out electric solenoid.