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HDGENE
HDGENE, Master Auto Technician
Category: GMC
Satisfied Customers: 4784
Experience:  Master Auto Technican
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My 2003 GMC Sierra 5.3 has a Service brake booster warning

Customer Question

My 2003 GMC Sierra 5.3 has a Service brake booster warning light on I believe that I have a vacuum booster I ran the test that suggested in the Chilton Service book
Submitted: 1 year ago.
Category: GMC
Expert:  HDGENE replied 1 year ago.

Ok if it is a vacuum brake booster it will have a large metal vacuum booster behind the master cylinder,if it is a hydroboost system it will have power steering hoses going to the hydroboost unit behind the master cylinder. Pump the brake pedal several times and hold your foot on the brake and start the engine, if the booster is ok it should make the brake pedal drop while holding down on it

Customer: replied 1 year ago.
It is definitely a vacuum booster and I did the test you just described the test passed
Expert:  HDGENE replied 1 year ago.

And the light stays on all the time?