I am not sure if your SE has maplights on the front center?
I have a '05 LE, which has the sunglasses holder/maplights/sunroof control.
I did install a Gentex dimming/compass/temperature mirro in my old '01 LE and it was really easy.
I popped out the maplight assembly, and then used a un-wound metal wire hanger (end wrapped in electrical tape) to poke from the gaping hole in the roof liner towards the top edge where it meets the windshield. Poke hard enough and sure enough, it will pop out next to the windshield. I then taped the mirror harness wiares to this, and the pulled the hanger back out to run the wires through the headliner out of the maplight "hole".
I bought an 18v DC lamp from radioshack, and soldered (or twist) a long wire to one end. I attached it to somethign ground in the car, and then wrapped the other end to a needle, and used it to poke around the harness behind the maplights. If you find a "live" wire, the lamp should light up. I found one that switched on/off with ignition, I peeled away the insulation, and then wrapped the power wire from the mirror wiring harness to this and then duct taped it.
The ground wire was wrapped around a screw that went into a body (subsequently, I did another one in a '92 maxima, and I couldn't find a screw behind the maplights, so I used a self-tapping sheet metal screw and drove it in to a metal bracket behind the maplights).
If you get the one that only dims and has compass, your wiring is done.
For the temp probe:
Take the same wire hanger, take off the electrical tape, and then using a file, file the tip of the wire to a blunt, round tip.
Look at the hood release handle. Follow the cable until it dissappears into the firewall. Spray ALOT of silicone lubricant into it, and then gently push the wirehanger wire through. If you are lucky, it will go through and you will see it either somewhere in the engine bay or inside the driver's side fender. If the wire is long enough, and you push long enough, it will eventually poke out near your driver's headlamps.
Take the temperature probe wire (it's really long), cut it about two feet from the end that attaches to the mirror harness, and then using electrical tape the cut end of the part that goes to the temp probe to the end of the now poking out hanger wire TIGHTLY. Slowly pull the wire hanger back from the inside of the car and you will have ran your temperature probe wire from the engine bay to the driver's side firewall. Un-due the tape.
Remove the plastic A-piller cover.
Run the same wire hanger down the now exposed "hole" on the driver's side dash until it peeks out around the hood release handle.
Tape the wire (that you just ran from the engine bay) and then pull up on the wire hanger until it goes up through the side of the driver's dash and it now runs out of the hold at the bottom of the A-piller. Undue the tape.
From the "Hole" where you popped out the maplights, push the wire hanger (tip wrapped in electrical tape to prevent scratching) above the headliner towards the top of the driver's side A-piller until the hanger wire pokes out. Tape the wire and then pull it.
Now, you should have a length of wire that runs from a temp probe harness in the engine bay, through the firewall, up the left side of driver's dash, up the A-piller, through the headliner, and out of the maplight hold.
re-attach the cut end of the temp line and then plug the hardness into the mirror harness.
Go position the temp probe somewhere you get and accurate reading.
You are done.