Toyota Repair: 90 toyota corolla, light fuse, dashboard lights

Question
The heat in my vehicle seems as if it may be shorting out.  When I start my vehicle the heat usually doesn't kick on at all.  As I continue to drive the heat kicks on and off sporadically.  Sometimes it works and sometimes it doesn't.  It also seems to be getting worse.  Also the light that lights up my dashboard so that I can see how fast I am driving doesn't work, all other interior lights are working fine.  This is a 90 Toyota Corolla.

Answer
If the engine reaches normal operating temperature there may be a problem with the heater core being clogged and there is not enough water curculating through it at times.
The dashboard lights and the tailights are on the same fuse, make sure that the tailights are working, if not look for the tail light fuse in the fuse panel it may be blown and try replacing it, if the fuse keeps blowing there is an electrical wiring problem or a short circuit in the tail light bulb holders, remove them and check for any burned wires or bad bulb sockets, if there is a problem there it should be obvious.