What could be causing the heater in my 98 Chevy S10 to blow out the dash vents when I've selected the floor or defrost options? Or, to blow in those places as well as in the face?
In most cases this is a symptom of a vacuum line that is broken. This vacuum line goes from the engine to the dash control unit, which in turn directs the flow of air high or low.
If someone has recently worked on the engine see if they knocked this vacuum line loose. If it is not obviously loose or broken then they shop may need to take a “smoke machine” to find exactly where the line is broken or disconnected. The smoke machine will “pinpoint” where the leak is. It may be inside the truck under the dash.
If you are local please give my shop a call for a free consultation and test drive.
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