1993 Trans Sport

Is there 2 problems here?

The tail lens are melting at the stop/signal lights.

The tail lights come on in the daytime; with the daytime running lights.
I noticed today that the daytime running lights (and tail lights) come on when you turn the switch to 'on' but do not start engine.

Could the break light switch have caused the brake lights to stay on (the brake light switch seems to be OK at present)? Could the tail lights and the brake lights stuck on, along with driving through a very hot summer trip through southern BC, cause the melting lens?

Is there a daylight sensitive switch that controls the tail lights from coming on with the daytime runners?

There is a twilight/darkness light sensor hidden under the left front speaker grille that turns the headlights ON to full power, with the tail lights.
The daylight running lights normally turn on at KEY ON at reduced power, and the tail lights are not connected with this curcuit. Reduced powr is obtained through voltage drop diodes, 2 in series built into a heat sink.
Position tail lights are low power, never able to melt the plastic. Brake/turn"hazard are high power....but should not stay on for long periods...unless some problem occurs elsewhere.
www.avigex.ca/xport/drl.jpg
more diagrams, photos at www.avigex.ca/xport