1993 Toyota Previa Interior and Rear Lights

I have a 1993 Toyota Previa that seems to have an electrical problem related to the rear lights and the dashboard lighting.

When I turn the car on and turn the lights on the head lights always come on and the brake lights work. But often the interior dashboard lights (not any other interior lights) and rear lights don't come on right away. When they do come on (randomly), they will do so at the same time (rear and dash lights). The longest I've had to wait has been about 30 minutes. The time it takes for them to come on usually relates to how recently the car was used and for how long the car was used previously.

Has anyone ever encountered a problem like this? Anything similar on a Toyota Previa?