Classic/Antique Car Repair/a/c blower problems

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Expert: - 4/30/2008


Question
#1 my a/c blower works only on medium speed , will not work on low or high speed. #2  compressor cycles on an off but  Cycles to 10psi before cutting out rising to 60psi before starting again ,is this normal. 1978 corvette factory a/c.

Answer
Question #2 is probably due to low refrigerant level in the system. The clutch should cycle to control A/C temperature but the low side pressure should not drop to 10 PSI. Question number one deal with the possibilities of a defective blower resistor, bad switch, or bad wiring. It is time to get on with a voltmeter and wiring diagram.
Brad

Classic/Antique Car Repair

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Brad Sears

Expertise

All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.

Experience

Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Publications
Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

Education/Credentials
More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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