I have a 95 mark viii. The computer display is having issues. I can no longer adjust the time. It always has 'door ajar', 'low coolant', even though the doors are closed and my coolant isn't low. Is this something that the ecm controls? How do I go about getting this fixed? tyvvm.
You likely have two separate problems.

The 'door ajar' warning is usually from a sticking door switch located in the door latch mechanism. Liberal application of WD40 with multiple opening/closing of the door will fix it 99.9% of the time.

The 'low coolant' warning is from a faulty low coolant sensor. Check that the float in the reservoir is indeed floating.
The display is ok, it just won't let you see anything else until you fix the door ajar issue like driller said.