Mechanics

NO AC FAN CONTROL

2007 Honda Civic • 55,000 miles

Originally, I had fan control but it was blowing hot air. I replenished the coolant an all of a sudden I have no power on any fan control settings. The fuse checked good. Disconnected the blower fan wires and checked for power-no power with key and fan control on. Disconnected the blower resistor wires thinking its the resistor-no power with the key and fan control on.
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Deo
March 23, 2012.



So do you have manual blower fan or automatic?Also all the blower fans I have seen run the ground thru the resistor to control the fan speed.

Saturntech9
Mar 23, 2012.
Not sure what you mean by manual or automatic. Shouldnt I get power though with the blower disconnect? Please elaborate.
Also, the initial problem was it was only blowing cold air with the temp setting on heat-sorry.

Tiny
Deo
Mar 23, 2012.
Do have a temp you can set for your a/c temp setting or do you just have a cold to hot slider control?With the key in the run position and the blower fan speed set at any speed you should have full battery voltage to the blower motor. The ground side of the blower fan is controled thru the blower switch then thru the resistor.

Saturntech9
Mar 23, 2012.
I have a round temp control knob(bottom left to middle top is for cold and middle top to bottom right is for heat).
Thats what I thought but I wasnt getting voltage at the blower and neither at the resistor. So im not sure if its the fan control head or switch. Not sure how to check that or even to begin taking the panel to access it.

Tiny
Deo
Mar 23, 2012.
At the blower motor, you must have voltage at the white wire. If voltage is not available, check the blower motor relay in underhood fuse box.

Check Fuse # 9 (40 A). It is for the blower motor.

KHLow2008
Mar 23, 2012.
There are several relays there, which one is the blower motor relay and how do I check if its faulty?

Tiny
Deo
Mar 23, 2012.
Checked fuse #9 (40A) and its good. Checked for voltage on fuse terminal and I got full voltage

Tiny
Deo
Mar 23, 2012.
Use a fused jumper wire across terminal 1 and 2 and check if voltage is available at the blower motor.

Swap the relay with the radiator fan control relay to test.

KHLow2008
Mar 23, 2012.
Im still not sure which relay is which. Could you please explain.

Tiny
Deo
Mar 23, 2012.
Again like I said before the the resistor is the ground side of the circuit so if you dont have power there. So with the key in the run position and the blower fan turned on and set at any speed do you power at the white wire at the blower motor?You never did say also is the under hood fuse box lid labeled or the fuse box itself to which relay is for the blower fan?

Saturntech9
Mar 23, 2012.
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