Is there a high speed blower motor relay?
Yes there is a high speed relay which sounds like it is out. Here is a guide to help test it and the blower motor wiring diagrams so you can see how the system works with the relay location below as well. Check out the diagrams (Below).
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?
How to test the blower motor resistor ( 1988-1993 pickup )?
CASE 2: All circuits tested had continuity where indicated in the test steps. This is good and is the correct and expected test result that tells you that the blower motor resistor is OK and not the cause of the blower motor speed problem. If your pickup’s blower motor resistor passed this continuity test, you can stop here.
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.
What are the symptoms of a bad blower motor relay?
3. Melted relay. Another more serious symptom of a problem with the blower motor relay is a burned or melted relay. Relays are exposed to high current loads and can sometimes get hot when they develop problems.
CASE 2: All circuits tested had continuity where indicated in the test steps. This is good and is the correct and expected test result that tells you that the blower motor resistor is OK and not the cause of the blower motor speed problem. If your pickup’s blower motor resistor passed this continuity test, you can stop here.
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.
Where is the blower control switch on the dashboard?
The blower control switch on the dashboard controls the circuit flow of the blower motor to adjust the voltage from low, to medium, to medium-high, to high. When on high, the circuit bypasses the blower resistor.
What causes a blower motor to stop working?
In a situation where the motor doesn’t work on any speed, the most likely causes are: a blown power supply fuse, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely. Blower motors generally don’t fail out of the clear blue.
What kind of motor does a variable speed blower use?
Variable speed blower motors don’t use a blower motor resistor. Instead they use a blower motor speed control or a power transistor. Variable speed motors are most often used in vehicles with automatic climate control.
How many volts does a red wire blower need?
If there is no sign of heat damage then check the following. With the 7 wire harness disconnected check for power on the red wire. It should have 12 volts at all times and it gets it’s power from the 40 amp blower fuse in the under hood fuse box.
Is there a red wire on the blower fan?
This is a 1995 Suburban K2500 4×4 6.5 TD. There isn’t a red wire at the fan. On the blower itself there is a purple wire (+12v whenever the blower speed is anywhere other than ‘off’) and black wire which should presumably be ground. I have tested the black wire for continuity to ground and theres almost none at all.
Why does my blower fan keep getting ground on Black Wire?
The AC system itself has trouble and has a leaky AC compressor (which I also bought a new one to replace!). I broke out the old trusty multimeter and it seems as though the purple wire on the fan motor gets +12v at all times with the fan switch anywhere but OFF.
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!
Why do I get no clicks on my blower fan?
I get no clicks from the relay under the glovebox – the only relay that clicks with the blower knob is the one under the fuse panel on the drivers side of the engine bay and I believe thats the AC relay. The AC system itself has trouble and has a leaky AC compressor (which I also bought a new one to replace!).