Fan Clutch, Chevy Trailblazer, Gmc Envoy, Ranier,Saab

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GMC Envoy/ Chevy Trailblazer Electronic Fan Clutch

Removal & Installation Instructions

Also Fits: Olsmobile Bravada, Buick Ranier, Isuzu Ascender, & Sabb Vehicles

GM Part #: 15293048, 25790869, 15192191

Dorman 622-001 Electronic Fan Clutch

AKA: Cooling Fan Speed Sensor, Electro-Viscous (EV) Fan Clutch, Electronic Fan Clutch

Symptoms that may require fan clutch replacement:

Excessive Fan Noise and/or Check Engine Light On

Possible Diagnostic Trouble Codes Set:

P0495, P1481, P1482, P1484


Fan Clutch Wrench Part #: J-41240 or J-46406

 This can usually be purchased at most Auto Zone or Advance Auto Parts Stores. We can also supply you this wrench with your fan clutch order. Please email or call us and we can add it to you order or you can usually add it when going through checkout. Please call us with any questions 1-866-770-2771

CAUTION: It is not recommended to disconnect the battery on any later model vehicle unless specified in repair instructions. Disconnecting the battery can cause the vehicle computers to lose valuable memory data and can actually cause driveabillity problems. If you do disconnect the battery, a computer relearn procedure must be done to bring vehicle back to normal.


 Remove Cooling Fan & Shroud

  • Remove the hood latch support

  • Disconnect the transmission cooler lines at the engine and release the lines from the fan shroud. NOTE: Many customers have stated that the cooler lines do not need to actually be disconnected, removing them from the shroud is all that is normally needed to get clearance

  • Remove the 2 upper fan shroud bolts

  • Drain approximatly 1 Qt. of coolant

  • Reposition the upper inlet radiator hose clamp

  • Remove the upper inlet radiator hose from the radiator

  • Remove the electrical connector from the shroud

  • Position the water pump so the bolts are aligned in the vertical position

  • Use the fan clutch wrench to loosen and remove the fan clutch hub nut. NOTE: This is removed by turning it in a counter-clockwise rotation while facing the vehicle. NOTE: The fan clutch wrench has 2 tabs that lock into the water pump to allow you to hold it while using the other piece of the wrench to turn the nut.More tips are below in our customer’s installation tips.

  • Unclip the fan shroud from the radiator side panels.

  • Tilt the radiator and the condenser forward

  • Lift the fan and the shroud up and out towards the engine to release the fan from the radiator inlet.

  • With the entire assembly out, remove the bolts retaining the fan blade to the fan clutch

  • Seperate the blade from the clutch


  • Install the fan blade onto the clutch and install the 4 bolts. Torque these bolts to 20 Ft./Lbs.
  • Install the fan & shroud onto the lip of the radiator bottom.
  • Install the 2 bolts into the upper fan shroud and tighten to 21 Ft./Lbs.
  • Connect the electrical connector
  • Clip the fan shroud to the radiator at the side panels
  • Install the fan clutch onto the water pump shaft and tighten in a clockwise rotation with the fan clutch wrench. The torque on this nut is 41 Ft./Lbs
  • Tighten or re-install the transmission cooler lines and clip them back into the fan shroud
  • Install the hood latch
  • Install the upper radiator hose and reposition the hose clamp
  • Fill the cooling system
  • Check with the dealer for any PCM software updates. These are very important!!

NOTE: Some vehicles require the PCM to be updated for a software problem with the fan clutch. You are surely familair with your home computer needing updates periodically. This is actually also true for the computers installed on your vehicle. Your vehicle has several computers installed and it is not uncommon for the manufacturer to come out with updates. Many of these updates are free and many are charged for. The electronic fan clutches on these vehicles are very common to fail, however sometimes all that is needed is a software update. The software for the fan clutch has been upgraded and also should be done when a new fan clutch is installed. The early model trailblazers, envoy’s, ranier’s, bravada’s, and Saab’s could actually have improved air conditioning function and have a ticking noise fixed by having a software update performed. Please check with your dealer by calling them and giving them your VIN to see if any updates are available. They are well worth getting even if they cost you money.

VIEW this FAN CLUTCH on our website here…


ASE Certified Auto Technician 16+ Years Of Auto Repair Experience

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26 Responses

  1. Dale says:

    I have already replaced one of these. The only thing I can add is that the fan clutch tool I borrowed from Autozone would not stay on the nuts on the water pump pulley. The large nut that goes on the shaft was tightened by an 800 lb. gorilla at the factory. To get the tool to work I loosened two of the nuts on the pulley and slid the clutch tool behind them and then tightened them down. The tool held steady while the pipe wrench loosend the big shiny nut. After you get it loose you can spin it with your fingers. Figuring this out was 75% of the time to repair. I also did not drain the coolant. Sucked out enogh with a turkey baster so when the upper hose was removed it did not spill a drop. Good Luck.

  2. sawzall says:

    I just replaced mine today.
    All I have in addition to Dale’s great tip is the step “Tilt the radiator and the condenser forward”. I’m not even sure how this is done without unbolting the radiator itself (which isn’t in any step)so here’s what I had to do…
    Once I get the shroud unfastened from side and top, I realized there’s no way to get the entire fan/clutch assembly out w/ the shroud. So I had to unbolt the fan blade first and let the clutch fall a bit so I could get the front/back clearance to wedge the shroud, blade and clutch out together. Had to do the reverse on the install. Get the shroud back in place w/ the clutch and blade floating around inside. Then start the thread on the clutch shaft to get it in place, then bolt the blade onto the clutch.
    Tools needed besides the Autozone fan clutch tool were a 13mm socket and 13mm wrench for the water pump and and fan blade and a smaller socket for the two top rad bolts. And some channel locks for the radiator hose clamps. Not a lot needed actually.
    I used a wet vac to suck out the coolant from the top of the rad.
    Total time barring some tool hunting, about 1.5 hours for a first time job.

  3. sawzall says:

    In addition, this saved me and anybody else about $400. This reseller has the best price on these anywhere, way below even an Autozone or CSK price. Even much better than a NAPA dealer discount. GM books this job at $550 parts/labor so all the legit mechanics will quote this as well.
    I verified my AC now blows cold right away and keeps the temp steady in slow/stop driving.

  4. sawzall says:

    One last thing or two, I never unbolted the hood latch support and am not even sure why its listed unless my 03 Trailblazer/Envoy is different than other 4.2L GM SUVs. The ridgid cooler lines definitely do not need to be removed, just pushed out of the retainers on the left (facing car) side of the shroud.
    The shroud mounts on bottom can pop out if you make the smallest adjustment to it so just make sure the two deals on the bottom are seated in the holes before you button it up.
    ALSO, Manually turn your blade when your done. Verify no rubbing on the shroud anywhere before you fire up the motor.

  5. Claude Berger on says:

    I made my own special tools. I used a 24″ metal bar with one 3/16″ hole at one end. The, I unbolted one bolts from the water pump and install my bar with a longer bolt. I used then a pipe wrench to unbolt the fan clutch. It was an easy job to do.

  6. karen says:

    When I turn the fan by hand and it is not free wheeling, is it safe to say the computer software will not fix this problen until the clutch fan be replaced first.

  7. Mark Wagner says:

    I wasn’t able to remove the shroud because the radiator inlet was covering it. I had to remove the fan from the clutch and then manipulate both pieces out separately. I appreciated the other instructions because they were very helpful.

  8. sawzall says:

    Has anyone gotten the PCM upgrade done at the dealer? How much did it cost?

  9. Joel says:

    We had a customer go to the dealer for the upgrade last week after installing the new clutch. They actually did it through the northstar system and didn’t even touch the car. The car stayed in the parking lot and it took about 15 minutes total. (15 minutes may not be as lucky for everyone). The cost was $85.00.

  10. garrett says:

    On March 25, 2008, Karen posted: If the fan clutch is very stiff to turn by hand at any time, is it safe to say that the pcm update will not correct this physical issue? Many good suggestions/tips here, as I too-grrrrrr-am now needing this after only 54k miles of service on my 2002 trailblazer, not reall happy with this one-lol-2 u-joints, front wheel hub assymbly, a/c problems continually, temp sensors x2, rear calipers sticking, master cylinder issues, interior lights that wont shut off—just to name a few-thank God warranty covered most of this

  11. Carl says:

    A few points, the radiator mount is the 2 bolts that face down on each side of the rubber block that holds the top of the radiator. They are just behind the rubber block on the top of the frame support. They are in a hole for each bolt.

    As for the fan clutch wrench, I did not have one, all I used was a crescent wrench on the big nut and hit the end of the wrench with a hammer. Hit the wrench towards the passenger side of the car, counterclockwise. Like a impact wrench.

    The pin on the electrical plug was loose and needed to be glued into place. Check yours to make sure it is in place before you assemble the parts. Fixing this took the most time in the hole process.

    Took about 1.5 hrs to do.

    It is easer to do than I expected!

  12. Gil says:

    Comments were great and really helped me. I might add that I had to use a 1″ wide by 12 ” long cold chisel to loosen the big nut from the water pump. The most difficult and dangerous and trying part of the job. I hit the left side of the nut with the cold chisel (purchased at Walmart for $10) with a ball ping hammer. It took a few good wacks to do the job. It easily unscrewed once it freed. Be sure to hit it counterclockwise. I tried the flywheel clutch wrench but could never get enough torque to do the job. This nut is put on at 41 foot lbs. Oh, I also had to remove the fan blade assembly from the clutch to get clearance (13 mm wrench) and top radiator hose losing a little coolant (pair of slip joint pliers) I then slipped the fan and fan clutch out on the top right side of the fan shroud bending the plastic guard back to gain access. I did also have to remove the 10 mm fan shroud bolts to allow clearance for the assembly to be slipped out. Next, I unplugged the electronic component. I did not have to loosen the transimssion hoses at all. Be sure to wear gloves to protect knuckles and also be careful working around the radiiator. I just reversed the procedure to reinstall the new fan clutch. I found it helpful to install two bolts in the fan attaching it to the fan clutch to help realign the big 32 mm nut tightened with the cold chisel hit clockwise. Finally, I reset the computer once the fan clutch was completely installed by simply disconnecting the positive battery post for 15 minutes. Reconnect battery post and start engine. Mine reset itself and cleared the service engine light. This job was not easy and I busted my knuckles because I did not wear work glooves. It was worht it because I did save about $350 doing it myself.

  13. Richard says:

    I just finished installing the fan clutch. The job was easy once I got the Fan Clutch wrench from Canadian Tire (I’m in Canada). At 1st it appeared that the wrench didn’t fit on the water pump bolts. I just had to turn the bolts a bit to align them and then the tool fit fine. I used penetrating oil on the fan clutch to ensure it was easy to remove. I used a large crescent wrench on the fan clutch and without the use of a hammer turned it counter clockwise and it came off without too much force.

    Once off it looked like it would be impossible to remove the shroud but I was able to bend the shroud enough to get it over the top radiator outlet and then it came out fine. Don’t forget to pop the transmission cooler lines off the shroud before you raise it up.

    Installation again was easy. You just have to ensure that the bottom tabs on the shroud fit into the bottom bracket area.

    That’s it. No need to remove the radiator, transmission cooler lines, etc… They were going to charge 3 hours labour. I took about 1 hour total time. So the original quote (in CDN $) was $1150.00. I got the part for $225 and of course no labour cost.

    Thanks for all the help. This forum is great.

  14. Richard says:

    I had one hiccup. It appeared that after the install the new fan clutch had the same problem as the old one. Turns out that you need to run the vehicle for a while before the computer learns how to correctly control the fan clutch. After about 8 starts and driving for a while the fan clutch works fine now.

  15. First of all this was not easy and the directions did not work. I also got the tools needed from advance auto. The tools did not work as they were designed to.
    1. remove the top radiator hose.
    2. remove two top shroud screws
    3. unplug the clutch fan
    3. pop the two lines on left bottom out of their holders
    4. using tool from advance auto unscrew two bolts from the water pump pulley slide the tool in and retighten the bolts.
    5. use a pipe wrench and breaker bar and loosen the large bolt on the clutch fan.
    6. unscrew completely and remove the four bolts fron the fan
    7. reach in and stretch plastic shroud and remove the clutch fan…this will take some maneuvering, but will work.
    8 squeeze the new clutch in the same way
    9. reconnect the fan
    10. screw the new clutch fan on, being careful it is going on straight and not stripping the threads, you may want to take a crow bar putting presssure from behind while you are screwing.
    11. hook the hose and shroud back up and plug in the clutch fan
    * The only part I actually removed was the clutch fan.
    * this seemed to be the only route to take on a 2003 trailblazer…wear golves
    hope this helps someone… and I appreciate the help from all of you, I almost gave up when the tools did not work properly, but I read how one of you improvised and undid the two pulley bolts and tightened them on the tool….thanks and good luck…it’s worth the savings!!

  16. AlCan says:

    Thanks for all of the great information – one piece remains totally missing for me though: where do I get the special fan clutch removal tool? I’ve been to Auto Zone and they gave me a 5-piece tool kit that identifies Ford and other non-GM vehicles. None seemed to work well. Is there a specific, better tool that someone can clearly identify for me?

  17. Chris Simpson says:

    thank all of you who have posted, i am not a mechanic but handy. I would just like to add 2 things to this post. the first is that a little wd-40 goes a long way on the nut going to the waterpump, broke right loose after i sprayed it and let it sit for a couple minutes. the second is to go ahead and replace the water pump $45.00 and the serpentine belt $26 while this is all open. the reason i learned this is because the new fan clutch would not fit on the old pump but spun freely on the the new water pum and made the job easy. it is only a couple extra bucks and if you havent replaced the water pump recently, it will save you from breaking that nut loose again which was the most time consuming part of the job. also check the tools that you rent to be sure they fit, mine didn’t i had to use a pipe wrench which makes it tougher than it needs to be. Thank you agian, hope my feedback helps someone else.

  18. Mike McDermott says:

    Just replaced my fan clutch (2003 Trailblazer); ran into most of the same problems. I had to lossen 2 of the water pump bolts, back them out, insert the fan clutch wrench behind them, and tighten the bolts on top of the wrench to keep it from slipping off. Once I did that I had to use a chain wrench on the fan clutch nut since I had very little room remaining. Removed the fan from the clutch prior to trying to get the fan and shroud out. I think that made it slightly easier to get the parts out. I got NO movement of the radiator/condenser forward as the instructions described. I reinstalled with the fan and clutch inside the shroud – was much easier once I could see how things fit together. Total time 4 hours; 2.5 to remove, 1.5 to replace.

  19. Mike McDermott says:

    One addition – the step in the removal process to unclip the radiator side panels could use some furtherexplanation. On each side of the shroud there are two L shaped tabs; the upper one (about 1/2 down the side of the shroud) points up and the lower on points down. They each go into a hole in the side panel; they are very difficult to get to, hard to see, and take time to get off. The one on the drivers side is especially hard to get to. I found a long screwdriver and pliers working from underneath to be the best approach.

  20. Roger Moore says:

    I have an 03 Envoy with a 4.2. I replaced the water pump and noticed the fam shroud hit the neck on the radiator. Itook a dremial tool and notched it out. My fan clutch just went out but don’t see any wires going to this clutch. Am i going to need a diferant clutch than this one or can this one be made to work.

  21. Carl says:

    I read and appreciated every one’s comments listed here. I felt confident that I could replace the fan clutch on my 03 GMC Envoy. Well…I was successful. After about a hour of trying to get the fan shroud off, I decided to unbolt the fan from the clutch and take out in two pieces. Probably not the best method because I put small markings in the radiator fins. I’m still not sure how the shroud comes out as I was not able to get enough clearance from the top hose coupling. Loosening the nut off the water pump slowed me down a little but a borrowed fan clutch wrench from AutoZone and pipe wrench worked. Start to finish was about 3 hours. Thanks for the help here and good luck to those who attempt this…………

  22. Billy B. says:

    I just took a pair of vice-grips and locked down the water pump pulley. Took a big crescent wrench and latched it onto the large nut holding the fan clutch to the water pump. One pull to the left and it came loose so easy it was not even mystical. The rest was ridiculously easy. And they wanted $500 to do this…..

  23. Vivian says:

    What is the size of the bolts that go to the back of the fan that holds the fan on/ 2002 envoy/ my mechanic lost them…great day

  24. Subhash says:

    I have recently replace the fan clutch (TrailBlazer 2007 LT) due the reduce engine power light comes on, and fan clutch wiring harness was short, after I replace the fan clutch my A/C not working, compressor not engaging. please help if someone fix the same issue. However I have remove the battery for sometime and check still no luck,


  25. Eric says:

    Subhash – Our 2005 Trailblazer was overheating at an idle, so my wife took it into a dealer. The problem was the fan clutch, including some electronic component that allows for computer control. They robbed us blind, as I have found to be the case with GM dealers. Parts and labor added up to $1200, which included 3.5 hours of labor as well as a $105 diagnostic fee. I recommend using an honest independent mechanic and after market parts. From doing some preliminary research, it seems like the entire bill could have been half of that. GM dealers are CROOKS.

  26. Kevin says:

    do you have instructions on how to reset the computer? is it easy to do, do I have to take it to somebody to have it done? thank you for your time

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