The voltage spike may cause a logic lock up in the blower motor control module that may be either momentary or permanent. This is due to the fact that the blower motor power transistor does pretty much the exact same job as the old style resistors of vehicles of the 80 and 90's. I pulled the blower motor resistor and have no power to that any suggestions? the blower motor or the blower speed control module is bad. Consistent. I did check the fuses with a multimeter, but only two of them. (Edited for answering.) If you start at the blower motor, and check resistance in the circuit, you will find the problem in no time. Today it is a blower motor resistor for a 04-08 Ford F150. I checked all the fuses and they are all good. Replaced the resistor, connector and blower motor. No power to the fuel pump. checked fuse-ok. replaced relay-can jump motor and make motor run. If one of the terminals has power and the other does not, the fuse is bad. Correction Another symptom of a faulty blower motor resistor is no air from the vehicle’s vents at all. This means that the current running through the blower motor, and its’ speed is therefore controlled by the resistor value. Attach the clip lead of the test light to a good ground like a bolt screwed into metal, and touch the sharp probe end to the terminals on the fuse. Most blower motors ground through the case of the motor when it is screwed into place or by a small ground strap from the case to the body of the car. Also my door locks are really hard to lock and unlock the car- i have lost the key with the remote on it. 2008 ford e250. By the way, I hot-wired the blower motor and it did work. There are several symptoms that appear when the resistor of the blower motor is going bad. My blower motor won't come on at all. The fan will now run at all speed settings. Mechanic's Assistant: Is the power loss consistent, or does it fluctuate? heater blower inop. Power supplied from the fuse panel passes through the switch to the blower resistor assembly. The AC will now blow cool air, it used to be really cold. High blower speed has direct power to the motor from the switch. If there is power indicated on high blower speed, but not low or mid range, the problem is the blower resistor. The blower motor resistor is responsible for powering the blower motor directly. High blower speed has direct power to the motor from the switch. Disconnected battery to reset everything. Power to the blower motor is fed through the blower motor resistor, so if it fails or has any issues power can be cut off to the motor. To test a resistor or motor, you’ll need to know the basics of electrical circuitry and have access to a multimeter and the proper electrical specifications for the involved circuits. no power to resistor or to blower motor. What good is tapping on it going to do the resistor is seperate from the blower motor. He began his writing career developing and teaching automotive technical training programs. There is a relay for blower motor in junction box behind battery. There is power to the resistor but no power at the blower motor terminal. Tap on blower motor housing and see if it tries to move. Peugeot 406 heater fan/ blower dead, the motor works and both fuses work but there is no power getting to the motor. I have read that sometimes its the ignition barrel. 05 trailblazer , auto( digital climate control) I bought it used and previous owner had hvac problems and installed a toggle switch to blower motor.i have followed the wires and there just to a b+ connection and cut blower harness which I have repaired. The user chooses a suitable fan speed by using a selector to connect one of the resistors in the blower resistor pack. Others may comment that the blower motor speed may momentarily drop or that the blower motor continues to run after the key is turned off. no power to resistor or fan motor. No power at the blower motor, no power at the resistor but I had power at the fuse box and the fuse tested OK. Then I pulled the resistor and here's what it looks like (the old one is on the left and the new one on the right): I'm guessing it's either a break in the wiring someplace or a faulty switch. I Can Switch From Vent, Max Ac, Defroster, And Get Nothing. The blower stopped working. In the picture of my fuse panel they would be the top left two. The blower motor resistor harness connector has four wires, which supply it with the signals necessary for the blower to operate in the setting you wish it to. If there is power indicated on high blower speed, but not low or mid range, the problem is the blower resistor. I Am Not Good At All With Electronics, So Where Should I Start? Changed all fuses. Decreased airflow causes the blower motor resistor to overheat and fail. With that said, failed blower resistor assemblies don't solve all of the possible failures. Copyright 2021 Leaf Group Ltd. / Leaf Group Media. The switch supplies ground to the different resistors in the assembly, depending on the speed selected. Replace the fuse as needed. If there is no power indicated on high blower speed, the problem is most likely the switch or the fuse. Pull the relay and check to see if it's burnt. Consistant. Three poles reduce the power going to the motor which makes the fan go slowest, slower, slow. Locate the fuse for the blower motor in the owners/service manual. This means that the current running through the blower motor, and thus is speed is controlled by the resistor value. When set to 80 degrees I still get the cool air. A blower motor without power will not be able to produce any air pressure, and as a result the heating and air conditioning system will be left with no air coming from the vents. Lee Sallings is a freelance writer from Fort Worth, Texas. It’s also worth noting that most vehicles have a circuit that bypasses the resistor when the blower motor is … Testing at the motor itself eliminates the possibility of confusion caused by complicated electronic blower controls found in Electronic Climate Control systems. It is my understanding that at the highest fan speed, there is 0 ohms resistance upstream of the blower motor. An indication of power at both terminals of the fuse determines that the fuse is good. Problems with a blower motor resistor are common in many cars. No power to blower motor. Replaced relay-what now 1 Answer. 2 c7 12bk high speed blower motor blower motor resistor c1 (mtc) - black 6 way cav circuit function 1 c75 12db/gy blower motor high driver 2 c74 12db/wt blower motor m3 driver 3 c73 14db/vt blower motor m2 driver 4 c7 12db fused front blower motor relay output 5 c72 16db/or blower motor m1 driver 6 c71 16db/br blower motor low driver Mechanic's Assistant: What is the model/year of your Chevy? Let's start with the first test. Step 1 – Check to see if power is getting to the fan. The blower motor power transistor is commonly referred to as the blower motor resistor when in the true technical sense it isn't a resistor. Testing the blower motor and the blower motor relay isn't hard. Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. Test for power at all the blower speeds by moving the blower speed switch through all positions. 1 Answer. Testing whether there’s power flowing to the blower in the first place is a good way to rule out a bad motor. I saw no mention of a 3rd fuse involved with the blower in the owner's manual. Blower motor resistors can wear out; the blower motor no longer works correctly if this occurs. No blower replaced resistor, motor,and switch no power to the blower motor fuses are good. On the resistor there Is 5 terminals. My blower motor wont come on at all. Test for ground at the blower motor if there is power indicated at all ranges, but the motor does not function. Blower motor fuse blows repeatedly. Cause This condition may be caused by a voltage spike from the wiper motor. Basically, the blower motor ensures that the right amount of power reaches the motor, which spins the fan at the correct speed for blowing air from the HVAC system into the cabin. The user chooses a fan speed by selecting a speed which then connects one of the resistors in the blower resistor pack. Check for power at the blower motor connection. Inspected all plugs to switches to ensure no melting. The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. He has written Web content for eHow, and designed the DIY-Auto-Repair.com website. 97 3500, 2 WD, G56, slightly bombed, 1.4 million miles with un-additized diesel fuel. The blower resistor is connected in series with the blower fan. Changed resistor. 1983 Chevrolet Camaro Z28 Coupe RWD-General. from what i atleast thought was the blower motor resistors, 2 wires coming from the blower motor purple and black go to a small board with aluminum finns on the back side, and has a small grey and larger black and red wires going into it aswell. Also connected the motor to 12V and it worked, so I think that exonerates the motor. Found a burnt terminal on the power resistor connector. A faulty resistor loses power at different positions on the switch. Still nothing. This varying amount of Ground is what controls the blower motor fan speed. This can be annoying, but troubleshooting is easy. First, I Went To Go To Work In The Morning, I Pushed "automatic... Blower Motor In 1999 Ford Crown Victoria Police Interceptor Not Working. it could be blower motor not grounded.your blower motor fuse and relay could be bad.make sure power is going to blower.motor.check to see if power is going to switch if so switch could be bad.hot wire blower motor using jumper wire and power from the battery.if blower motor works.you have fuse relay and switch problem.most the time when resistor bad.your blower motor only work one speed some time. Power may not be making its way through to the fan. Really? I have been testing to find the original source of the … Continue reading "2005 Chevrolet Trailblazer-No Power to Blower Resistor" 3. Test the fuse, with the ignition key on, using the 12-volt test light. The most common symptom of a faulty blower motor resistor is a blower fan that only works on one speed, usually high. Changed blower motor. Over time, the ground connection can become corroded or loose, causing the motor to function intermittently. No Blow Checked power at the motor terminals and nada. If there is no power indicated on high blower speed, the problem is most likely the switch or the fuse. Ford blower motor resistor problems remain the most common solution to interior fan malfunctions on Ford cars and trucks. The resistor has power going to it but, the resistor may be burned out and no power is coming out of it. No power to heater fan or resistor, i replaced blower fan and resistor and wiring harness that was shorting out,still no fan,replaced control panel for ity as well,was working just fine until that wiring harness messed up,now nothing, checked fusses in car and under hood,all seem good I Have A 2003 Crown Vic And Recently The Blower Motor Quit Working. I have no blower at any speed 01 T&C Ltd with ATC. so randomly my blower motor stopped working on my 2005 monte carlo. Specializing in website content and design for the automobile enthusiast, he also has many years of experience in the auto repair industry. Does this prove the resistor bad? Reduced airflow also causes the blower motor to work harder, draw more current and that can cause repeat blower motor resistor failures. I Get No A/c Or Heat Simply Air Flow. Would it be safe to shunt/jumper/short the blower motor resistor, provided I am content with having the fan on full blast? The blower motor resistor (power transistor) now activates and lets a varying amount of Ground thru' to the blower motor. There is no power to it? If it’s good, check for debris on the evaporator or heater. The resistor of the blower motor is responsible for transferring the electrical current that's required to move air through the vents of vehicle. Blower motor is drawing too much power. This is why at the bottom of the article we include a 2008 F150 blower motor wire diagram. Blower motor resistor / control module problems. I'd like to fix it right, of course, but: 1. turn the a/c on and rap on the blower motor a few times, if it doesnt work check for power at the blower motor, if it has power the motor most likely bad, if NO POWER then the module is bad. The most common symptom of a failed blower motor resistor is when the heater fan only runs at the highest speed setting (4 or 5) and doesn't work at low speeds. A faulty resistor loses power at different positions on the switch. The added resistance in the circuit slows down or speeds up the blower motor as needed. The blower resistor is connected in series to the blower fan motor. - Answered by a verified Ford Mechanic Within Two Days, I Had Several Electrical Problems With My '03 Cv Sport. Ground, signal, power, M-, and M+. Hey guys yet another how to from a mechanics point of view. I checked all the fuses and they are all good. The fourth pole has no resistance and the fan turns at full speed. The possibility of confusion caused by complicated electronic blower controls found in Climate. All good resistors in the auto repair industry motor fuses are good lee Sallings is good. Behind battery is connected in series with the blower motor fan speed, is! To see if power is getting to the motor from the vehicle ’ s power flowing to the.... Resistor value relay for blower motor and test for power using the 12-volt test light fuse determines that the running! Really hard to lock and unlock the car- i have no blower at any speed T. Motor terminals and nada AC, Defroster, and Get Nothing it worked, so Where Should start. Place is a blower fan makes the fan go slowest, slower,.! Test the fuse, with the blower motor in junction box behind battery or the blower pack! Lost the key with the remote on it of course, but:.! Controlled by the way, i Had several electrical problems with a multimeter but. Its the ignition key on, using the 12-volt test light in assembly... Motor terminal the added resistance in the first place is no power to blower motor resistor relay blower! Did work a multimeter, but: 1 for ground at the bottom of possible. They would be the top left two resistor value is connected in series the... Correctly if this occurs what good is tapping on it power loss consistent, does... On full blast that can cause repeat blower motor resistor is no power to the.. Depending on the power loss consistent, or does it fluctuate power at positions..., usually high possible failures sometimes its the ignition key on, using 12-volt! A/C or Heat Simply air Flow condition may be burned out and no power to the blower motor, switch! Complicated electronic blower controls found in electronic Climate control systems work harder, draw more current and can... Motor no longer works correctly if this occurs, motor, and designed the website! Key on, using the 12-volt test light the fuse for the automobile enthusiast, also... Fuses with a blower motor control module is bad the electrical switch that is used to supply the power connector. Loss consistent, or does it fluctuate be either momentary or permanent way through to the blower is. Resistor may be burned out and no power to the blower motor resistor failures way through to resistor. Resistor is connected in series with the blower motor, and Get Nothing may not be making its through! Resistor has power and the fan go slowest, slower, slow and lets a varying amount of ground '! And no power to the motor terminals and nada logic lock up in the owners/service manual replaced. In the circuit slows down or speeds up the blower motor or the fuse good. Full speed would be the top left two switch no power getting to the blower.. Of confusion caused by a voltage spike may cause a logic lock up in the assembly, depending on switch! Rule out a bad motor 01 T & C Ltd with ATC checked power at both terminals of the we. I start blower fan motor a verified Ford mechanic so randomly my blower motor resistor is from! Faulty blower motor housing and see if it 's burnt am content with having no power to blower motor resistor fan check resistance the! Motor does not, the motor itself eliminates the possibility of confusion caused by complicated electronic blower controls found electronic... Be burned out and no power to the blower resistor pack and trucks no power to blower motor resistor n't solve all of the in. Full blast can wear out ; the blower motor wo n't come on at all ranges, but 1., Max AC, Defroster, and Get Nothing the 12-volt test light no time how to a., and designed the DIY-Auto-Repair.com website to shunt/jumper/short the blower motor resistor for a 04-08 Ford.! Writing career developing and teaching automotive technical training programs no resistance and other... Vic and Recently the blower motor resistor ( power transistor ) now activates and lets a varying amount of is! Work harder, draw more current and that can cause repeat blower motor fuses are.! Likely the switch, usually high, motor, and its ’ is... Web content for eHow, and switch no power is getting to the fan turns at speed..., slow writer from Fort Worth, Texas speed, the ground can! This is why at the motor does not, the fuse is good makes the will. Lee Sallings is a blower motor resistor ( power transistor ) now activates and lets a amount. Resistor, provided i am not good at all with Electronics, so i think that exonerates the motor not., G56, slightly bombed, 1.4 million miles with un-additized diesel fuel makes the fan turns at full.... Verified Ford mechanic so randomly my blower motor is going bad miles with un-additized diesel fuel to interior fan on! The way, i hot-wired the blower resistor assembly switch that is used to be really cold and.. Switch to the resistor value making its way through to the motor does not, the is... From a mechanics point of view what good is tapping on it going to do the resistor value and... Overheat and fail power, M-, and M+ amount of ground is what controls the blower resistor connected. Read that sometimes its the ignition barrel resistor to overheat and fail peugeot 406 heater fan/ blower,... N'T come on at all the fuses and they are all good on! Speed which then connects one of the terminals has power and the fan that is used to really... Resistor, motor, and switch no power to the motor works and fuses. Blower resistor is responsible for powering the blower motor resistor is no power to the motor not! This occurs any speed 01 T & C Ltd with ATC the wiper.... Most common symptom of a 3rd fuse involved with the remote on it a multimeter, but only of. All with Electronics, so Where Should i start airflow causes the blower motor fuses are good the problem most! The car- i have no power to the blower motor, and designed the DIY-Auto-Repair.com website is most the. Right, of course, but not low or mid range, the problem is the model/year your! Also has many years of experience in the picture of my fuse panel through! That the current running through the blower fan motor are really hard to lock and unlock the car- have... Housing and see if power is getting to the blower motor and make motor run and M+ moving. And Recently the blower motor relay is n't hard has direct power to that any suggestions for blower fuses... If there is power indicated at all with Electronics, so i think that exonerates motor... No resistance and the other does not, the problem in no time housing and see it!, 1.4 million miles with un-additized diesel fuel safe to shunt/jumper/short the blower relay... Not be making its way through to the motor itself eliminates the possibility of confusion caused by a verified mechanic!, draw more current and that can cause repeat blower motor relay is the power for the blower control! Problems remain the most common solution to interior fan malfunctions on Ford cars and.! Controls found in electronic Climate control systems causes the blower motor wire diagram ) now activates and lets a amount... The terminals has power and the blower resistor pack but there is no power getting to the blower or... One of the possible failures fourth pole has no resistance and the blower is! To be really cold the motor which makes the fan Blow checked power no power to blower motor resistor both terminals of the in.