How to tell if your blower motor relay is bad?

How to tell if your blower motor relay is bad?

Symptoms of a bad heater blower motor resistor

1. Fan does not work at all, so no air comes out of the vents.
2. Fan only works on some speeds and not others.
3. Fan only works on the highest speed.
4. Fan runs all the time and can’t be controlled with the fan switch.
5. You see smoke coming out of the vents.

How do you know if your ceiling fan capacitor is bad?

The capacitor is usually a black box inside the switch housing of the fan. If the case appears burnt or melted in any way, that is also the sign of a bad capacitor and it should be replaced.

How is the speed of a blower fan controlled?

The blower resistor is connected in series with the blower fan. This means that the current running through the blower motor, and thus is speed is controlled by the resistor value. The user chooses a suitable fan speed by using a selector to connect one of the resistors in the blower resistor pack.

What happens when the a / C fan is too low?

The switch really contain two switches. One of them cuts the CCU clutch signal and turns off the compressor if the pressure is too low, (2.5 bar) or too high (27 bar) in the A/C refrigerant circuit system. The other switch set the condenser cooling fan speed to high if the pressure exceeds 17.5 bar.

How is the condenser cooling fan pressure switch connected?

The condenser cooling fan pressure switch has GND connected to pin 3 and closes to pin 2 (brown/black) if the pressure is over 17,5 bar. The CCU is connected to the DME engine control unit, and this signal enable the CCU to stop the fuel supply being cut off on the overrun.

Is it better to set the fan speed to low or high?

The faster the fan spins, the quicker it can move air in the house. This should equate to cooler temperatures, but the unit will be louder, use more electricity, and you will notice the increased air current. You will want to adjust this to you preference. I would start at low for a day and work your way up.

Where does the low speed fan relay go?

Click to expand… The low speed relay needs to have keyed power going to pin 85 unless you want the fans to stay on. You could also put a timed relay going to that pin to have the fans keep power for what ever time you set it to. Also that fan draws a lot of amps at startup on high.

How does a high speed blower motor work?

In the highest fan speed state, the blower resistor is bypassed completely and the fan is effectively connected directly to the car’s battery, allowing maximum current to be supplied to the blower motor.

Is the low speed fan connected to the high speed fan?

In the example included to the right, we can see cooling is connected to high speed, the heat is connected to medium speed, and the low speed is not being used (it’s just parked). From our previous example, let’s pretend we’re looking at a 60 kBTU furnace with a 2.5 ton AC attached to it, and we’re in Chicago.

What happens when a blower motor relay wears out?

Without it, the AC system will not be able to circulate any heated or cooled air. The blower motor relay controls the current used to power the blower motor, and is subject to the constant on and off switching. Over time, it can eventually wear out.