94’ mitsubishi eclipse wireing probs

U was putting in my new radio and my dash lights went out. If i touch a certain wire together they come on and stay on until i hit the switch to turn them on, then they go off. i completely unhooked the radio to see if i had done something wrong, the problem still exists. I have checked my fuses and they are not blown. Any ideas? I used the wiring diagram on this website.

Also, what is the constant vs switched 12 v? i had to get a reverse wire harness for the radio and the car so not oall of the wores match perfectly.

Thanks!

constant 12 volts is also sometimes called "memory" or "+battery".  It's a wire that is always getting power straight from the battery, regardless of whether or not the car is turned on.  When the car is off, this wire gives the head unit a tiny bit of power so it doesn't lose the time and station presets, etc.  When the car is on, this wire is the one giving the head unit it's main power.

The switched 12 volts wire (sometimes called "accessory") only has power going through it when the key is in the "ACC" or "ON" position.  Without 12volts on the head unit's switched wire, it will not turn on.  But obviously if you were to give it a constant 12 volt connection to its switched wire, it would always be on even if you had your car turned off.

Unless you really really want the dimmer/illumination functions (keep in mind many aftermarket head units don't even support this function), then you should just tape off these wires and not even connect them.  If you hook up a dimmer wire or illumination wire incorrectly, it is possible to damage your vehicle's electronics.

What wiring harness(es) did you purchase?  A standard harness (Metra 70-1743) and a reverse harness (Metra 71-1743) ?  Or just the standard harness?

Did you check all the fuses for continuity with a multimeter?  Sometimes even if a fuse looks good it can still be blown or damaged--this has happened to me on more than one occasion.

Make sure you're not connecting to the dimmer wire (just tape it off).  I don't know if the reverse harness has a dimmer wire; if so, I suppose you could connect it but since the 70-1743 harness doesn't have a dimmer wire in it, it won't do you any good and will just complicate things.  According to the diagram it's BLACK / YELLOW  but you should, as always, use a DMM to test all wires first.

The illumination (GREEN / WHITE according to the diagram) should be hooked up to the ORANGE / white or orange wire of the reverse harness.  There should only be one wire in the whole harness that has orange in it so it should be pretty straightforward.  And like I said if you decide not to hook this wire up just make sure the head unit end (if present) and the factory wire end are taped up.

Also you'll need to run a separate ground wire for the head  unit as there is not a ground wire in the standard wiring harness.  It just needs to be touching a piece of metal back there that looks like it runs to the chassis of the vehicle.  Verify it will your DMM though.