Do you have a lamp test switch on your instrument panel? If so, flip the switch to test the bulbs. If the lights dont come on, then you need to replace the bulbs. If they do, then the problem with the temp and oil pressure is probably the senders on the engine. Wiring typically fails last. As far as the tach goes, the sender is near the flywheel on the back of the engine. It should have a specific resistance (which escapes me right now). If it doesnt meet this resistance, the sender needs to the replaced.

Since all this stuff is out, you may have a break in the wiring harness. Get some help to check the continuity of the wiring from the source to the panel. It might just be the power source to the panel.

Isnt troubleshooting electrical systems fun [Linked Image from sailthebay.com]