Current drain through blower control module
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Joined: May 2002
Posts: 79
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From: The Netherlands aka "Absurdistan"
Current drain through blower control module
This is for a 1987 Corvette coupe with the C68 electronic air conditioning.
I'm having a current drain of 200 mA through the blower control module, that is the module in top of the evaporator housing on the right side of the engine bay, the one with 2 connectors on it, one with a red and green wire, and one with four wires. In order to establish if this module is bad I hope you can help me out.
The red wire has always 12V on it through a fusible link. It loses current through the green wire, this is the one that goes to the compressor clutch and 25A fuse.
What i need to know is this: When you unplug both the connectors from this module and you put 12V on the module pin where the red wire goes, and you measure for Volt on the module pin where normally the green wire goes (directly next to the Constant 12V pin), do you then measure 12V or 0V?
Julius
I'm having a current drain of 200 mA through the blower control module, that is the module in top of the evaporator housing on the right side of the engine bay, the one with 2 connectors on it, one with a red and green wire, and one with four wires. In order to establish if this module is bad I hope you can help me out.
The red wire has always 12V on it through a fusible link. It loses current through the green wire, this is the one that goes to the compressor clutch and 25A fuse.
What i need to know is this: When you unplug both the connectors from this module and you put 12V on the module pin where the red wire goes, and you measure for Volt on the module pin where normally the green wire goes (directly next to the Constant 12V pin), do you then measure 12V or 0V?
Julius
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Joined: Dec 2000
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From: San Diego, Ca
Re: Current drain through blower control module (fast not first)
The wires do different things. The fusible link is power when turned on by the dash controls (much like a relay). The green wire completes the compressor clutch circuit to ground which is a driver within the module. Both wires will have 12 volts. The red at all times; the green with the ignition on as it's power is from the a/c fuse, through the clutch coil and back to the module. Jumper the green wire to ground (ignition on) and the compressor clutch should engage. An unusual draw at the module (assuming you measured at the red wire) would be because it's not turning off. Is the blower motor running with the ignition off? Check blower output which is the purple wire. To see if the dash controls are at fault, check the brown or blower signal wire for voltage. Shouldn't be any with the ignition off. If there is, the wire is shorted to voltage or the assembly is powered up - is the display lit with the ignition off? Check the draw on it's memory power too which is from the courtesy/clock fuse. Compressor clutch signal is the dkgreen/yellow wire. It shouldn't have any power on it with ignition off either. If the controls and wiring checks out, the module is bad.
Thread Starter
Advanced
Joined: May 2002
Posts: 79
Likes: 4
From: The Netherlands aka "Absurdistan"
Re: Current drain through blower control module (SunCr)
The module behaves normally asides from the draw when the ignition is off. Blower etc works normal. With ignition off I only have voltage at the red wire, so this is also normal.
What I need to know now is this: If someone has a spare module away from the car, no connectors connected, and you put 12V on the pin where normally the red wire goes, what do you measure on the pin where normally the green wire goes?
What I need to know now is this: If someone has a spare module away from the car, no connectors connected, and you put 12V on the pin where normally the red wire goes, what do you measure on the pin where normally the green wire goes?
