This is a quick video I made to show you the location of the HVAC Temperature Blend Door Actuators on a 1997-1999 Cadillac Deville or Similar Seville, Eldorado or maybe even slightly newer Caddy’s.
The tools you will need are a 1/4” Ratchet(long handle preferably), 7/32” socket, 5.5mm socket, torx bit set for removing glove box, needle nose pliers, flat blade screw driver.
From my understanding, the bottom blend door actuator is the driver side, and the top one is the passenger side. You can also always turn one sides temperature from the hottest setting to the coldest setting to see which one moves, unless both of yours are bad.
Both blend door actuators are the same part numbers. If you have an issue with the air blowing out of certain vents, and not others - I use to have a problem with my defrost or front most vents I believe - there’s a small diameter vacuum line on the passenger side of the engine bay that goes through a wire harness behind the strut tower, that’ll be vacuum for the HVAC controls, if that is disconnected like mine was you’ll have issues. I believe there’s another actuator somewhere for the blend MODE but I will eventually make a video on that one as well.
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