Sorry I should have looked rather than rely on my memory. I too have the same items installed in the same location. There are markings indicating it is a Ford product with the following numbers E3 HT-2A451-BA and 003953-92 as best I can tell. I search both numbers and variations of each in google and found the Ford Service part number 2A451 is a vacuum pump used to control the heat and AC controls. The prefix identifies the year of manufacture, vehicle designation, and the suffix the series revision.
If it runs continuously I suspect there is a vacuum leak somewhere.
Hope this helps,
Full timing from Washington State