Chevy Trailblazer: Electric Fan Clutch Failure
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Date: 2020-08-05
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Comments and reviews: 10
Jason
i have had two trailblazers for close to 11 years now and love them both, but they both always have problems with this fan setup. the last time i replaced them both i got the lifetime warranty fan from autobone about 3 years ago. anyways i did not have the tools to observe rpm, or the scope to monitor the square wave of the speed sensor, as you have but i know i have had problems with these fans for some time now. i have to replace them about once a year sometimes more. in each vehicle, i have gotten pretty fast at it lol. anyways. i read there was a gm service bulliten on these fans and gm recommends a pcm flash and a new redesigned fan for these vehicles but i not remember why, maybe to increase fan speed at low rpm to aid with ac system not cooling off fast enough? on to my symptoms that lead me to having to warranty swap these out: 1 if i let the vehicle sit and run for more than say 30 minutes or so the fan clutch starts making crazy squeaking and rattling sounds at the tale end of that fan clutches life span and i usually replace it the next day. 2 sometimes i notice the clutch will not engage and my ac stops blowing cold and engine temps rises. 3 sometimes i notice the clutch stays fulled engaged and it sounds like a turbo prop is under the hood. i know i should have went with oem. seems like both the oem and aftermarket design of these are bad. just my two cents. awesome video as usual. i wish i had a mechanic like you in my area, then i wouldnt have to worry about getting shafted while dealing with incompetence.
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i have had two trailblazers for close to 11 years now and love them both, but they both always have problems with this fan setup. the last time i replaced them both i got the lifetime warranty fan from autobone about 3 years ago. anyways i did not have the tools to observe rpm, or the scope to monitor the square wave of the speed sensor, as you have but i know i have had problems with these fans for some time now. i have to replace them about once a year sometimes more. in each vehicle, i have gotten pretty fast at it lol. anyways. i read there was a gm service bulliten on these fans and gm recommends a pcm flash and a new redesigned fan for these vehicles but i not remember why, maybe to increase fan speed at low rpm to aid with ac system not cooling off fast enough? on to my symptoms that lead me to having to warranty swap these out: 1 if i let the vehicle sit and run for more than say 30 minutes or so the fan clutch starts making crazy squeaking and rattling sounds at the tale end of that fan clutches life span and i usually replace it the next day. 2 sometimes i notice the clutch will not engage and my ac stops blowing cold and engine temps rises. 3 sometimes i notice the clutch stays fulled engaged and it sounds like a turbo prop is under the hood. i know i should have went with oem. seems like both the oem and aftermarket design of these are bad. just my two cents. awesome video as usual. i wish i had a mechanic like you in my area, then i wouldnt have to worry about getting shafted while dealing with incompetence.
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Abdullah
Thanks for that video, Im currently having the same problem on a 2006 LR3 with code P0480. Replaced the fan but no improvement. Hooked my original fan on to another LR3 and the fan ok. So now I now the problem if not from the fan but it will somewhere from the connector at the fan to the ECU. And here where Im lost. I got the wiring diagram for the fan, but I dont have a scope to check the wave form, Im using a maxisys P809 as scantool and a good multimeter. Any tips Will be much appreciated.
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Thanks for that video, Im currently having the same problem on a 2006 LR3 with code P0480. Replaced the fan but no improvement. Hooked my original fan on to another LR3 and the fan ok. So now I now the problem if not from the fan but it will somewhere from the connector at the fan to the ECU. And here where Im lost. I got the wiring diagram for the fan, but I dont have a scope to check the wave form, Im using a maxisys P809 as scantool and a good multimeter. Any tips Will be much appreciated.
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Mister
Eric, So many comments. Own a 2002 TB with 160K trying to keep it operational for few. I would just like to convert the damn thing to a bi-metal fan clutch like on my 2000 s10 with 4. 3 v6. They attach to water pump similarly. or maybe remove it all to together and add an electric fan. any consequences to vehicle operation other than the check engine light? Thank you. If I must replace this with new, do you recommend a certain manufacturer of replacement parts?
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Eric, So many comments. Own a 2002 TB with 160K trying to keep it operational for few. I would just like to convert the damn thing to a bi-metal fan clutch like on my 2000 s10 with 4. 3 v6. They attach to water pump similarly. or maybe remove it all to together and add an electric fan. any consequences to vehicle operation other than the check engine light? Thank you. If I must replace this with new, do you recommend a certain manufacturer of replacement parts?
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William
When I was working for Chevrolet at the dealer level, we saw so many of these coming in and the customers were complaining that it was a transmission issue. It sounded like a jet airplane thought that because of the fan noise would increase with the speed of the car, like direct drive, but we knew we had to put a new electric mechanical fan clutch assembly on it and also reprogram the PCM for the new fan clutch assembly. I believe there was a TSB on this.
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When I was working for Chevrolet at the dealer level, we saw so many of these coming in and the customers were complaining that it was a transmission issue. It sounded like a jet airplane thought that because of the fan noise would increase with the speed of the car, like direct drive, but we knew we had to put a new electric mechanical fan clutch assembly on it and also reprogram the PCM for the new fan clutch assembly. I believe there was a TSB on this.
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David
I've got a fan question. Say I buy a new V-8 F-150 and I buy and add a after market fan run by a switch in the cab. I would look for a fan maybe a quarter to a third the size of the radiator. I would put it between the grill and the radiator toward a corner of the radiator. But I would only use it in heavy stop and go traffic or really hot days. But what I want to know is by adding this fan would it cause more trouble then it would solve?
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I've got a fan question. Say I buy a new V-8 F-150 and I buy and add a after market fan run by a switch in the cab. I would look for a fan maybe a quarter to a third the size of the radiator. I would put it between the grill and the radiator toward a corner of the radiator. But I would only use it in heavy stop and go traffic or really hot days. But what I want to know is by adding this fan would it cause more trouble then it would solve?
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christopher
Ahhh the dreaded fan clutch. I had so many problems with that as well. Ended up changing it to a thermal and sending pcm to a tuneshop to delete codes. No problems since. I do think that they used a fan clutch because the engine is all aluminum which gets hotter much faster than a regular engine with cast block with aluminum heads. However letting it reach 260 before full command in fan clutch is just absurd in my opinion
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Ahhh the dreaded fan clutch. I had so many problems with that as well. Ended up changing it to a thermal and sending pcm to a tuneshop to delete codes. No problems since. I do think that they used a fan clutch because the engine is all aluminum which gets hotter much faster than a regular engine with cast block with aluminum heads. However letting it reach 260 before full command in fan clutch is just absurd in my opinion
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andrew
Hey finally thank I can afford a snap on scanner now there probably 5 years old to upgrade my shade tree mechanic lol how come you dont use yours anymore and how you like the bydirction on it and go head spit it were you get your schematics and literature keep up the good content my sister truck doing the same thing now I no what it is not a regular clutch I thank it's made by nasa
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Hey finally thank I can afford a snap on scanner now there probably 5 years old to upgrade my shade tree mechanic lol how come you dont use yours anymore and how you like the bydirction on it and go head spit it were you get your schematics and literature keep up the good content my sister truck doing the same thing now I no what it is not a regular clutch I thank it's made by nasa
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MrOnemanop
I have a similar vehicle (2002 Envoy) with a newly wandering Temp. gage. I was just going to through a new thermostat into it (Tricky job, last time took me 2. 5hrs) But seeing this video makes me think there are processes beyond my ability to diagnose, so I'll go see a pro who can look at inputs such as these to truly discover what's going on. Thanks Eric!
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I have a similar vehicle (2002 Envoy) with a newly wandering Temp. gage. I was just going to through a new thermostat into it (Tricky job, last time took me 2. 5hrs) But seeing this video makes me think there are processes beyond my ability to diagnose, so I'll go see a pro who can look at inputs such as these to truly discover what's going on. Thanks Eric!
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Lackey
Just like PWM on the HVAC blower only with a sensor instead of human and knob. BTW Eric, the sensor on that fan works like the one in the reformatted hard drive PC. 3 wires, 5V ground and a PWM output to see if the fan is working. Had to reprogram one when they changed fan models.
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Just like PWM on the HVAC blower only with a sensor instead of human and knob. BTW Eric, the sensor on that fan works like the one in the reformatted hard drive PC. 3 wires, 5V ground and a PWM output to see if the fan is working. Had to reprogram one when they changed fan models.
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TheMarshall85
Eric!
Would you be able to do a video on test lights and what you have, what you recommend etc in terms of led and an incandescent. Ive been into power probe for years but Im looking for a good test light or a good couple of test lights
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Eric!
Would you be able to do a video on test lights and what you have, what you recommend etc in terms of led and an incandescent. Ive been into power probe for years but Im looking for a good test light or a good couple of test lights
reply
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