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Already did the relocation of new vacuum canister a few years ago. Was working fine. Yesterday while on a road trip with AC on max the air would stop coming from the vents and go to the dash/defrost and then a few seconds later the floor then back to the vents. Did it 3-4 times within an hour. Throttle position doesn't affect it. Can't make it repeat, just does it randomly.
Any ideas? I know going from vents to dash involves both vacuum actuators in the dash.
TIA
JKaz
My ‘03 F150 has stayed put on defrost for a while after a short bout wavering back and forth depending on acceleration needs. I took a scope to the passenger side corner yesterday and found the hose mangled just outside the firewall grommet. A fun time will be had there! Lots of those hose couplers get crusty, too. May have to replace some as well.
Also, I believe the check valve is behind the radio. I guess it holds vacuum at times. May be worth replacing now, anyway.