83 733 HVAC overhaul (archive)

Summer's coming quickly in South Texas and thought the heat works great, the A/C blowing through the defrost got old last year so I decided to dive in and fix it all at once:

One very important note in the troubleshooting archives is the small fuse in the left side of the glove compartment area. Simply cleaning the contacts seems to have eliminated the intermittent clicking in my pushbutton controls. Who knows what a new fuse might do...

Bad vacuum diaphragms in the cowl area - fresh air vents control units have small rubber diaphragms that the vacuum lines apply suction to to open/close the fresh air vents. Driver side has 2 vacuum lines - one purple / one green while passenger side has only one - white. Will replace both with new from dealer parts & report pricing if interested...

Bypassed vacuum tank T connection - vacuum tank tests okay but the rubber grommet around the T seemed to leak. Plan to replace later...

Obvious leak - hissing sound - in driver footwell area - similar control unit to fresh air vents - bad rubber diaphragm also... This one was difficult to remove - long regular screwdriver helped to remove circlip attached to blower housing.

Final stage resistors - yep, these too! Fan only runs on high. BMW dealer's gonna love me.

Thanks to Grant, Callan and others in the archives for the accurate info that has aided in this repair.

Dale
83' 733i
San Antonio, TX

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