A/C Heater blower motor '92 Custom Cruiser
October 15th, 2010, 08:49 AM
#1
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Join Date: Jan 2009
Location: Dallas Texas
Posts: 1,565
A/C Heater blower motor '92 Custom Cruiser
Need a little technical expertise. A/C heater blower motor erratically will quit working. Compressor engaged, just the blower quits, on any speed. My repair shop replaced the Blower motor control resistor, and it worked...until last night coming home from hearing some great music at our local favorite, the Balcony Club. Any ideas as to where to go at this point? My thinking, maybe a loose wire somewhere. Car has 205K miles (runs great, and a great road car) w/no major repairs.
October 15th, 2010, 09:01 AM
#3
Oldsdruid
Join Date: Dec 2007
Location: Southside Vajenya
Posts: 10,284
Now, if you had said 1972 or even 1982 Custom Cruiser, I'd take a stab at it. But by 1992, so much stuff was circuit board and relay controlled that you need a year-specific electrical manual.
October 15th, 2010, 12:48 PM
#4
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,259
Aron,
I have a similar problem with my 84 Custom Cruiser. Check every connector in the wires between the blower motor and the switch. GM unfortunately pinched some pennies with electrical wiring in the 1980s and early 1990s, with the result that some connectors and terminals are marginal for the current being carried. In the case of the 307 powered cars, there is a four wire connector that mates the engine harness to the HVAC harness. One of the wires in this connector is a relatively heavy gauge red wire that powers the blower motor. This connector (at least on my car) is an unsealed Packard 56 style, so crud gets into the terminals. As resistance goes up, so does heating of that pair of terminals, which causes arcing, which increases resistance, which increases heating, etc, etc. I've had to replace the melted connector body on more than one occasion.
Similarly, on the 77-90 cars there is a single wire connector behind the heater control head in the dash that powers the blower speed switch. Similar problem with terminal resistance and ultimate failure.
Unfortunately, I doubt that the 91-92 cars have the same wiring harness as the 77-90 cars, but I'm willing to bet that there is a similar terminal resistance problem somewhere. Disconnect, inspect, and clean the terminal in every connector in the blower motor circuit.
I guarantee that the problem will be in the last one you check...
I have a similar problem with my 84 Custom Cruiser. Check every connector in the wires between the blower motor and the switch. GM unfortunately pinched some pennies with electrical wiring in the 1980s and early 1990s, with the result that some connectors and terminals are marginal for the current being carried. In the case of the 307 powered cars, there is a four wire connector that mates the engine harness to the HVAC harness. One of the wires in this connector is a relatively heavy gauge red wire that powers the blower motor. This connector (at least on my car) is an unsealed Packard 56 style, so crud gets into the terminals. As resistance goes up, so does heating of that pair of terminals, which causes arcing, which increases resistance, which increases heating, etc, etc. I've had to replace the melted connector body on more than one occasion.
Similarly, on the 77-90 cars there is a single wire connector behind the heater control head in the dash that powers the blower speed switch. Similar problem with terminal resistance and ultimate failure.
Unfortunately, I doubt that the 91-92 cars have the same wiring harness as the 77-90 cars, but I'm willing to bet that there is a similar terminal resistance problem somewhere. Disconnect, inspect, and clean the terminal in every connector in the blower motor circuit.
I guarantee that the problem will be in the last one you check...
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