No heater or a/c

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Old May 23, 2026 | 01:36 PM
  #1  
John Donovan's Avatar
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John Donovan
 
Joined: Dec 2023
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From: Saint John N.B.
No heater or a/c

Lost my power to my heater a/c today bench tested the relay and blower motor both are working fuse is good power on both sides but no power at the fan speed switch is there something else I'm missing any information or suggestions would be a big help.
Old May 23, 2026 | 04:35 PM
  #2  
Sugar Bear's Avatar
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John,

Year, model, factory or aftermarket AC?

Is the connector at the fan switch melted at all?

Where is the power being checked to the fan switch? Back of the switch?
Old May 23, 2026 | 06:03 PM
  #3  
fleming442's Avatar
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From: Mt.Ary, MD
G bodies have a plastic connector near the firewall that melts.
Old May 24, 2026 | 04:04 PM
  #4  
John Donovan's Avatar
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John Donovan
 
Joined: Dec 2023
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From: Saint John N.B.
No power to fan switch

It's an 83 oldsmobile ninety eight regency the fuse is good on both sides but no power at the fan speed switch no melted wires it was working then stopped and like I said previously I bench tested the relay and blower motor and they work fine and there is no power going to them as well
Old May 25, 2026 | 06:22 AM
  #5  
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From: Northern VA
The 1977-90 B/C body cars have the same connector and same problem as the G-body cars. The HVAC harness mates to the engine harness at a four-pin square connector on the passenger side of the engine compartment, near the distributor. That four pin connector actually has only three wires in it. One is a heavy-gauge red wire that is the power source for the HVAC system. This terminal is undersized for the current and since it is not sealed, it gets wet and corrodes in the engine compartment. This causes resistance that causes heat that eventually melts the connector body and prevents the system from getting powered. I've owned five of these B-body cars and all of them have had this problem at one time or another.
Old Today | 03:48 PM
  #6  
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John Donovan
 
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From: Saint John N.B.
No heater or A/c

Well I found the plastic connector by the distributor I have power in the connector but still none at the fan speed switch and no power out of the plastic connector
Old Today | 05:25 PM
  #7  
joe_padavano's Avatar
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This connector?





When you tested for power, did you reconnect the two and back probe the connector to the HVAC to verify power on that red wire AFTER the connector? If so, then you need to continue tracing the circuit back under the dash until you find where the power stops. This isn't going to be diagnosed by remote control, only brute force tracing of the circuit.
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