HVAC Bi-level mode inop.

[buickguy62]

Hi ,

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My new (to me) 1990 Reatta has inoperative bi-level outlets-no air comes out regardless of the set mode. About 85% of the air goes to the defroster, about 15% to the floor.

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I didn’t see any error code when I ran the BCM diagnostics.

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Cruise control does work, so I likely have vacuum to the door actuator.

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I overrode the air door output signal (BS01) and monitored the air door actual position feedback (BD23), and it tracked the driven input, so I believe the actuator is working. I assume the feedback is on the actuator, not the door.

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I’m afraid I may have a problem with the linkage from the actuator to the door, I read a ‘horror’ case a few days earlier, can’t find it now—must have been on this forum, where the rod to the door was slipping or broken from the actuator, hope I don’t have to go there.

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Any suggestions are welcome.

Thanks,

Tom

[buickguy62]

Oops, looks like BD23 is the temp control, BD24 is the air delivery mode, (improper air delivery), back to some more diagnostics.

Tom

[Guest Corvanti]

here's one: http://forums.aaca.org/f116/blend-door-actuator-320570.html

try using the "Search Forum" that is below the "Advanced Search" next to "Forum Tools".

[Guest steveskyhawk]

When you lose vacuum to the HVAC system it defaults to defrost. The source of vacuum starts at the engine. Begin there and inspect every inch of vacuum line until it passes through the firewall. My guess is that the problem is under the hood.

[buickguy62]

Vacuum line from engine thru firewall is OK---however, it had slipped off the input to the HVAC programmer, I reconnected it and all is well, I love easy fixes!!

Thanks for all your help,

Tom