Blower motor switch
Thread Starter
Instructor
Joined: Mar 2013
Posts: 180
Likes: 21
From: Chesterfield Mo
Blower motor switch
The blower motor on my 75 with air will only turn at low speed as the blower speed switch is progressed from low to high. If there is an increase in speed it is hard to tell. This condition existed before the heater controller was rebuilt with all new switches. The rebuild did not correct the problem. I am electrically challenged. Is there a resistor that could cause this? Can the blower motor be defective? How to troubleshoot this problem. I have digital and analog meters but don't know how to proceed.
The A/C is inoperative. The compressor is out of the car. Would this have anything to do with the problem.
I have only had this car a short time. I'm trying to sort out some gremlins.
The A/C is inoperative. The compressor is out of the car. Would this have anything to do with the problem.
I have only had this car a short time. I'm trying to sort out some gremlins.
Pro
Joined: Aug 2013
Posts: 591
Likes: 3
From: Monroe Washington
Mine worked with all stages when I bought the car... Then have me high only for a while(shut off in any other position)... And now has gone back to working at all speeds again... I'm sure it just needs a good cleaning... Will do once it acts up again... The fan should definitely push pretty hard... And the motor should work or not, and is replaced for $15 at the local parts store... But typically it's the bearings that go out.. Anyways... Is first try checking out the switch and try to clean the contacts... See if it helps...
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The speed is controlled by the resistor in the top of the blower housing on the outside of the car. Yellow blue and green in this schematic are the three lower speed wires.
In all lower speeds, the relay feeds power to the blower motor on the purple wire at 64A, it will pass voltage to 968.... When you turn the high blower on, the relay switches the power to the orange (high blower) wire 40 in the picture.
If you put a volt tester at the motor plug, you should be able to see the voltage change when you switch speeds inside the car.
You might also check:
The high blower relay on the evaporator case and make sure the wires are clean and plugged in. It's common for the orange wire connector to melt.
If you don't have power on the orange wire when in high blow... go to the driver side and check, there should be a inline fuse holder there that might have an issue too.
Willcox
Last edited by Willcox Corvette; Jun 6, 2014 at 11:00 AM.
Thread Starter
Instructor
Joined: Mar 2013
Posts: 180
Likes: 21
From: Chesterfield Mo
Mine worked with all stages when I bought the car... Then have me high only for a while(shut off in any other position)... And now has gone back to working at all speeds again... I'm sure it just needs a good cleaning... Will do once it acts up again... The fan should definitely push pretty hard... And the motor should work or not, and is replaced for $15 at the local parts store... But typically it's the bearings that go out.. Anyways... Is first try checking out the switch and try to clean the contacts... See if it helps...
Thread Starter
Instructor
Joined: Mar 2013
Posts: 180
Likes: 21
From: Chesterfield Mo
The speed is controlled by the resistor in the top of the blower housing on the outside of the car. Yellow blue and green in this schematic are the three lower speed wires.
In all lower speeds, the relay feeds power to the blower motor on the purple wire at 64A, it will pass voltage to 968.... When you turn the high blower on, the relay switches the power to the orange (high blower) wire 40 in the picture.
If you put a volt tester at the motor plug, you should be able to see the voltage change when you switch speeds inside the car.
You might also check:
The high blower relay on the evaporator case and make sure the wires are clean and plugged in. It's common for the orange wire connector to melt.
If you don't have power on the orange wire when in high blow... go to the driver side and check, there should be a inline fuse holder there that might have an issue too.
Willcox
