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79 - Air through heater vents when lights are on


Old 07-13-2018, 10:44 PM
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Default 79 - Air through heater vents when lights are on

I recently refreshed the A/C systems and it appears to work just fine (during daylight hours). Tonight it was the first time I drove the Vette in the night with the A/C on. Airflow was coming through the heater vents only. Once I turned the lights off, the air-flow was restored through the center and side vents.

Is this unusual or a known issue?
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Old 07-13-2018, 11:23 PM
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Years ago I restored a 1979 that was fire damaged... (never again will I do a fire car).... But I had a similar issue.... The problem was the ground at the number 1 body mount. The fire caused the ground to corrode and not make good contact. My issue was when I'd turn the headlamps on the gauges would stop working in the center console. So I'd suspect that this might be a similar issue for you.

You might check the main wire ground at the A pillar (see number 3 in the picture below) and/or run a temporary ground from the number 1 mount to the frame and see if this fixes your issue....


Last edited by Willcox Corvette; 07-13-2018 at 11:25 PM.
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