the miprom is confused it doesn't know what to do. the doors aren't actually opening are they? you may have a bad input board, or the computer is seeing something that should be in the opposite state when the doors are set to open. a loose connection on the input boards is a possibility, see if the connection terminal wiggles when you jiggle it .

Bad input board or power supply

John Jay: The doors open until the reset occurs, then shut immediately like it would if you take it off inspection.

Philly: I changed the power supply board. No luck.

Thanks guys.

Bad CPU.

when you say reset, does the cpu blink reset? do you have the new style cpu? usually they are not intermittent. The older ones are plug and play. The newer style you have to fuss with a little. Is the door board a 104 style, you could have a flaky door board. Just thinking, don't mean to confuse the issue.

Follow up: Spent another day troubleshooting. Found car works
normally on Fire Service and Independent, but reset Led
on power board and CPU keep flashing when attempting to
run on automatic.

Replaced every single board in both racks with same
results. As a last resort, replaced input rack.

Problem disappeared after replacing rack.

Talk about weird problem.

Ive had this one before, replaced the 5volt regulator on the top rack. problem solved. FYI before i replaced it properly, i just temporarily used some jumpers to connect the regulator and let it hang off the rack. that was not a good idea, as it only worked for a few minutes, I figured that was not the problem, but when i went to remove it, i burned my finger, that baby was really hot. learned my lesson, it needs to be connected to the rack to dissipate the heat, i was amazed at how hot it got in such a short time. when it gets hot it really lowers the output which caused many resets. Hooked it up properly, and worked great.