Why does my heater not work on high speed?

Why does my heater not work on high speed?

Heater blower motor will not work on high speed? I have replaced the black bosch relay behind the glovebox, the blower resistor and the blower motor and still cannot get the blower to work on high. I remember in older model years of gmc’s and chevys that their was a high speed blower relay that caused this issue.

What happens if the blower motor only works on high speed?

In other designs, the failure of 1 resistor means you lose only one speed. However, most car makers bypass the blower motor resistor completely when you move the fan speed switch to high. If your blower only operates on its highest speed, chances are you have the series type of blower motor resistor. This is the most common failure mode.

What happens when you change the fuse on a heater blower?

If the fuse is blown, replace it and then try the blower. If the fuse blows right away, your car may have a bad blower motor or some other problem in the system. If the blower works when you change the fuse, you may not be out of the woods yet. When the motor gets old and tired it will draw more current through the wires than a new motor.

When to replace a heater blower motor switch or relay?

When the motor gets old and tired it will draw more current through the wires than a new motor. It may still draw enough current to blow the fuse after it runs for a while. In that case, a motor replacement is in order. Step 1: Disconnect the battery. Put on your safety glasses and disconnect the battery at the negative cable.

Heater blower motor will not work on high speed? I have replaced the black bosch relay behind the glovebox, the blower resistor and the blower motor and still cannot get the blower to work on high. I remember in older model years of gmc’s and chevys that their was a high speed blower relay that caused this issue.

Why does heater blower motor increase in resistance?

As part of our comfort and luxury, the blower speed is one of the most adjusted settings in a car, and so the resistance of the blower motor is constantly being put under stress, which can eventually lead to motor failure; too much humidity in the atmosphere can lead to an increase in resistance.

What kind of blower does not work on high?

1997 GMC C1500 Heater/AC Blower Will Not Work on HIGH. 1997 GMC C1500 Heater/AC blower will not work on HIGH. I have replaced the black BOSCH relay behind the glovebox, the blower RESISTOR and the blower MOTOR and still cannot get the blower to work 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.

Why does my GMC heater blower not work?

I have replaced the black bosch relay behind the glovebox, the blower resistor and the blower motor and still cannot get the blower to work on high. I remember in older model years of gmc’s and chevys that their was a high speed blower relay that caused this issue. If there is a high speed relay, I can’t find it. Any suggestions?

Why does my blower motor only work on high speed?

Many, many times a car or truck will come into the shop with the customer complaining that their blower motor doesn’t work, or only works on high speed, etc. This is usually the case after a blower resistor failure on one or more speed settings.

Why is my AC heater fan not working?

This sounds more like a problem with high speed fan relay. On the low speeds, the fan relay routes the voltage thru the resistor block. When you switch to high fan speed, the relay switches over to supply full voltage from the battery to the fan motor.

This sounds more like a problem with high speed fan relay. On the low speeds, the fan relay routes the voltage thru the resistor block. When you switch to high fan speed, the relay switches over to supply full voltage from the battery to the fan motor.

I have replaced the black bosch relay behind the glovebox, the blower resistor and the blower motor and still cannot get the blower to work on high. I remember in older model years of gmc’s and chevys that their was a high speed blower relay that caused this issue. If there is a high speed relay, I can’t find it. Any suggestions?

Why is my blower motor only working at high speed?

The first thing that needs to be determined is the type of noise that is present and the possible sources. Rattling or knocking noises while… The blower motor only working on high speed is a common symptom of a failing blower motor resistor; but the fact the radio stopped working at the same time is unusual.

Why is there no ground on my blower motor?

It seems, too, that the black ground wire on the blower motor (accessible from just below the dash) has NO ground potential. I ghetto jumpered a 16 gauge wire from the back of the metal clip on the ground wire to the dashboard impact bar/brace and the fan turns at variable speeds with the knob!

What to do if your heater fan does not work?

Now gently grab ahold of the red and black wire connector and wiggle it if your fan came on you have found the problem. Now if this worked for you remove the positive battery wire from the battery because the red wire at this connector remains hot.

It seems, too, that the black ground wire on the blower motor (accessible from just below the dash) has NO ground potential. I ghetto jumpered a 16 gauge wire from the back of the metal clip on the ground wire to the dashboard impact bar/brace and the fan turns at variable speeds with the knob!

Why is my heater fan not working on my 2003 Chevy?

Heater blower motor fan won’t work in 2003 Chevy pickup half ton. Replaced motor had power on both wires in motor plug. I grounded the black one out now no power on either one.

What’s the second speed on a dasshboard blower?

This will usually go before the switch which is much more difficult to access inside the dasshboard. Lost 2nd speed. Live with it. 1,3, and 4 speed are sufficient. Blower motor does not work on 1 or 2 speeds. I have yet to attempt repair. I replaced the blower motor resistor but selection 4 (high) don’t work.

Many, many times a car or truck will come into the shop with the customer complaining that their blower motor doesn’t work, or only works on high speed, etc. This is usually the case after a blower resistor failure on one or more speed settings.

This will usually go before the switch which is much more difficult to access inside the dasshboard. Lost 2nd speed. Live with it. 1,3, and 4 speed are sufficient. Blower motor does not work on 1 or 2 speeds. I have yet to attempt repair. I replaced the blower motor resistor but selection 4 (high) don’t work.

The first thing that needs to be determined is the type of noise that is present and the possible sources. Rattling or knocking noises while… The blower motor only working on high speed is a common symptom of a failing blower motor resistor; but the fact the radio stopped working at the same time is unusual.

Why is my blower not working in Hi ( 5 )?

The usual failure of the resistor pack is if it works in HI (5) but not in any other mode or just a few modes. When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok.

The usual failure of the resistor pack is if it works in HI (5) but not in any other mode or just a few modes. When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok.