Question about 2000 Chevrolet Blazer

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2003 Blazer - Oil coming from climate control vacuum connector

I have a 2003 Blazer. The selector switch (vent / heat / defrost) stopped working. It would not change from dash vent to defrost or heat. I did have a spare switch and went to replace it. Upon disassembling, I noticed a light machine type oil coming the vacuum lines. I cleaned it up, replaced the switch and all was well for about 3-4 weeks. Now the problem is back & there is a noticeable vacuum leak from behind the dash.

Any suggestion would help

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  • Chevrolet Master
  • 6,982 Answers

May sound silly but take a short length of hose and put one end to your ear and use the other end to probe for the leak. It will be substantially louder as you get nearer to it. As far as the oily stuff in the lines, I can't think of anywhere it could be coming from unless the master cylinder is leaking into the power booster and somehow getting into vacuum lines...but this should not happen because any fluid in there would be drawn into the engine, and, the master would be low??? Try to find the leak first and deal with the other thing later...it may turn out to be a "nothing" item.

Posted on Apr 15, 2009

  • caseyauto Jan 19, 2011

    There is a TSB on this, replace the vacuum switch on the transfer case.

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vacuum control motor-i4bq0ig33y1522pr2d2rrkk3-2-0.gif

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vacuum lines hvac 03 grand marquis-13qahwfdndst2y1hypmr2cdq-4-2.gif Item Part Number Description 1 White Air inlet door 2 Yellow Floor/defrost door 3 Red Floor door 4 Blue Panel door 5 Black Source vacuum 6 - Not used


VACUUM APPLICATIONS CHART-ELECTRONIC AUTOMATIC TEMPERATURE CONTROL Switch Port Vacuum Harness Hose Color Func- tion Manual Override Selector Buttons OFF MAX A/C NORM A/C VENT FLOOR FLOOR/ DEF DEF 1 White Air inlet 2 Yellow Floor/ panel (partial) 3 Red Full floor 4 Blue Panel 5 Black
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