is there anything else on that circuit like a clock?i dont have the same instrument panel as you so i cant check mine. could be something else doing it unless you pulled the fuse and let the car sit for a longer period than three days and it started. how old is the battery? an older battery can do it. dont forget there are more electrical systems in these cars. another thing you may want to check is the output of the alternator.when mine did it the output was about 13.7 volts which a friend who scanned it for me (after i bought it) said it was kind of a low reading. replaced it and stopped having the problem.
eddie208902011-07-02 18:45:42

on my '89 dash panel, there's constant power to the dash panel and I believe it's for the climate control memory settings - temp, fan speed, etc. I think the '88 panel is the same

The LCD fuse should be hot all the time. It keeps the processor memory alive in the cluster. It should only have around 18-22 milliamp draw on it, key off.
One thing...never use a test light to check any of the circuits on the cluster...use a good multimeter. A test light can give false info, as well as damage some sensitive circuitry in the processor. Checking the fuse with a light is ok, but it will not show the exact voltage going thru the fuse. The test light will light up with 8volts, so you'll assume the fuse is good, but the system will not work properly with less than 12 volts.
I have a good article on finding battery drain issues somewhere. I'll see if I can locate, and post it. It may be at the shop....