Any one using this I6 Trailblazer Plug and Play Fan Kit from PCM OF NC?

snoozer

Well-Known Member
I have been trying to decide if I want to go with this fan kit or just install a fan clutch for a 2008 into my 2003 Trailblazer. I am getting tired of dealing with the electric fan clutch, looking for alternative solutions to it.
I know either way I would have to get the PCM setup so I don't get any fan codes, but I noticed on a couple of the reviews on this electric fan kit mentions of upgrading the alternator to a higher output one.
Is this really necessary to go with a different alt, I don't have any extra stuff drawing from the electrical system?
Here's the link to the kit:
http://www.pcmofnc.com/product/i6-trailblazer-plug-and-play-fan-kit-3/

Thank you,
Mark
 

Mooseman

Moderator
Go with the thermo fan and tune. A lot cheaper than the e-fan setup and less troublesome. There have been some issues with them, including fan motor failure and there is no easy way to activate them with the A/C.

Trust me. I used to be on the e-fan Kool-Aid and went with the thermo clutch. Best decision I ever made.
 

Mektek

Well-Known Member
Go with the thermo fan and tune. A lot cheaper than the e-fan setup and less troublesome. There have been some issues with them, including fan motor failure and there is no easy way to activate them with the A/C.

Trust me. I used to be on the e-fan Kool-Aid and went with the thermo clutch. Best decision I ever made.
Sure there's an easy way. Connect fan power to the AC clutch connector and both will run together. I converted a Nissan pathfinder to dual electric fans that way and it worked well for many years. The relay running that circuit is rated for 30a - more than enough to power everything. You could also switch a separate relay from that source and power it independently if your fans draw a lot of power.

Just as a FYI I drove the TB 20 miles through moderate city traffic with no fan at all. The temp needle crept slowly upward at long stops, but nothing to be concerned about. If your cooling system is in good condition, electric fans will do fine.

I have a experiment I plan to conduct eventually - powering the fan from the fan clutch power and rigging up a hall effect sensor on the efan. That should make it work without setting codes. Just a theory for now.......
 
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HARDTRAILZ

Moderator
The real issue is the efan will not flow enough for the completely unbalanced cooling system in the 4.2. Forget the triggering of it and realize it will never move as much air as the system is designed to need.
 
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snoozer

snoozer

Well-Known Member
Go with the thermo fan and tune. A lot cheaper than the e-fan setup and less troublesome. There have been some issues with them, including fan motor failure and there is no easy way to activate them with the A/C.

Trust me. I used to be on the e-fan Kool-Aid and went with the thermo clutch. Best decision I ever made.
Thank you very much. I most definitely don't need any more fan headaches.

When installing the thermo fan clutch in place of the electric one do I still use the same fan that's in my 2003?
The shop who installed the clutch has finally agreed to refund my money for the part & install whatever clutch I want if I bring it in.
So after clutch is replaced will it cause any issues driving it for awhile until the PCM can be tuned?

Once again thank you
 

Mooseman

Moderator
Sure there's an easy way. Connect fan power to the AC clutch connector and both will run together.
If you want to kill your alternator and wreak havoc with your voltages, sure. You have the clutch AND the fans cycling with the A/C. You don't want your fans cycling with the clutch.

When installing the thermo fan clutch in place of the electric one do I still use the same fan that's in my 2003?
Yes, exactly the same setup except you don't plug in the fan connector.

So after clutch is replaced will it cause any issues driving it for awhile until the PCM can be tuned?
You will get a CEL for the fan being disconnected, that's all. Everything will work and run as before. Only issue is that you won't know if another code comes up behind it so you should get the tune done ASAP or check the codes once in a while.

Again, I'd stick with a good name brand (not Dorman or parts store house brands) like Hayden for the clutch. For the tune, lime-swap.com (@limequat ) is good and cheap, $99 shipped. Might as well get other stuff done at the same time like shift firmness and a performance boost. He is very well versed with our platform.
 
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snoozer

snoozer

Well-Known Member
If you want to kill your alternator and wreak havoc with your voltages, sure. You have the clutch AND the fans cycling with the A/C. You don't want your fans cycling with the clutch.



Yes, exactly the same setup except you don't plug in the fan connector.



You will get a CEL for the fan being disconnected, that's all. Everything will work and run as before. Only issue is that you won't know if another code comes up behind it so you should get the tune done ASAP or check the codes once in a while.

Again, I'd stick with a good name brand (not Dorman or parts store house brands) like Hayden for the clutch. For the tune, lime-swap.com (@limequat ) is good and cheap, $99 shipped. Might as well get other stuff done at the same time like shift firmness and a performance boost. He is very well versed with our platform.
That is my plan then. I will get a hold of limequat & go from there.
Thank you very much for all of your assistance.
Back when I used to fix my own vehicles & help others with theirs I always used name brand parts, but when you forced to rely on someone else to do your work who knows what cheap garbage they are installing.
 

Mooseman

Moderator
Glad we were able to help. :2thumbsup:
 

JPutnam

Well-Known Member
Mooseman, do you have a part number for the clutch? I was going to buy that kit but now you have me leaning to the thermal. Never had a problem with the one on my Tahoe the 18 years I have have had it, and she takes a beating! Im afraid of going to jail for spousal abuse for all the things I have done to poor Christine!
 

Mooseman

Moderator
Hayden 2851, $75 on Amazon. Same on RockAuto but shipping not included.
 
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snoozer

snoozer

Well-Known Member
Mooseman, do you have a part number for the clutch? I was going to buy that kit but now you have me leaning to the thermal. Never had a problem with the one on my Tahoe the 18 years I have have had it, and she takes a beating! Im afraid of going to jail for spousal abuse for all the things I have done to poor Christine!
Here's a link to the Hayden on Amazon:
https://www.amazon.com/dp/B00276J4ZW/_encoding=UTF8?coliid=I1YUWRJ8W36JPU&colid=IGA65576047L

Link to ACDelco for $98.82 on Amazon: https://www.amazon.com/dp/B0016HZY2K/_encoding=UTF8?coliid=I118EDD205ADBQ&colid=IGA65576047L

I myself I am ordering the ACDelco it's a little bit more money, but figured to go original equipment this time around.
 

Locksmith

Well-Known Member
Go with the thermo fan and tune. A lot cheaper than the e-fan setup and less troublesome. There have been some issues with them, including fan motor failure and there is no easy way to activate them with the A/C.

Trust me. I used to be on the e-fan Kool-Aid and went with the thermo clutch. Best decision I ever made.
Brother Mooseman, Please explain how, if I swap out to a 08 thermal fan clutch on my 03 4.2, do I get Lime-Swap to get rid of the codes and bring up performance? What do I have to send them? Please explain in plain English, so an old guy with 1978 mechanic technology can comprehend!
 

Mooseman

Moderator
@limequat would be the one to talk to. Basically, you send him your PCM with what you want done and he returns it to you to reinstall. No more fan codes.
 

rufusthedog

Member
I installed the pcmofnc Plug and Play kit this weekend. I didn't want to have to send out my PCM to get re-programmed and I didn't want to $250 for a PCM programmer so I took the harness off the old clutch fan and wrote a simple program for a $5 Arduino uno to test if I fake a pulse to the PCM would the light go out......and it did. I have to do more testing but it looks promising.
 

Mike534x

Well-Known Member
@rufusthedog I was going to say, if you had to send out the PCM they (PCM of NC) give you a free voucher to have it programmed for the kit. All you're paying is the return shipping on it.
 

rufusthedog

Member
@rufusthedog I was going to say, if you had to send out the PCM they (PCM of NC) give you a free voucher to have it programmed for the kit. All you're paying is the return shipping on it.
I knew about their PCM programming for free, I just didn't want be without my Saab for the time it would take to ship to NC from CA. I was also curious if would work or not.
 

Mektek

Well-Known Member
I'm not sure, but I think that if there is a mismatch between the commanded speed and actual speed it will eventually set a code.
If it doesn't you could make the arduino do double duty - reading a temperature sensor and AC clutch power to control the fan while sending the fake pulse signal.

Keep us posted - this may be the best efan solution so far.
 

rufusthedog

Member
I went ahead and designed a little PCB and printed a little housing. I hooked it up today and I drove to the dump and so far it is keeping the CEL out. I'M thinking about expanding the design to read the temperature and control the fan to vary the fan speed instead on/off like it is now.



20190927_180902.jpg20190928_113813.jpgOp20190927_180855.jpg
 

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rufusthedog

Member
It looked like the clutch fan put out 5 pulses per revolution so I picked 10 KHz(2000 RPM). I'm still testing to ensure the CEL stays out.
 

rufusthedog

Member
FAIL#@%*.

It did finally throw PO495 code. I will try to read the PWM control signal and vary the pulses accordingly.
 

rufusthedog

Member
I played with again and read the data while is was plug-in and I had it way too high. I cut back the pulses and now it is reporting ~600 RPM. So far so good but I will have test it more.
 

KylePlacke

New Member
Personally, I Just did mine not too long ago too. I used a set of fans i had laying around to justify an mpvi2 and 2 credits to do it myself because this is my daily too.

Glad to find active forums :smile:
 

rufusthedog

Member
I think my main problem was I was sending out too high of a RPM response. I read the speed the computer was expecting and it was around 600 RPM and I originally was sending back over 4000. I cut it back to around 600 and I hasn't thrown a code for since and it has been over a week now and driving it everyday. I will let everyone know if it does throw one but so far so good.
 

rufusthedog

Member
How about reading the 12v control signal and then sending out a corresponding 5v signal ?
That will be next option if lowering the RPM doesn't doesn't fix it. My thought is the RPM shouldn't change much if the electric fan doesn't get overwhelmed and can keep up with the cooling demand.
 

TJBaker57

Well-Known Member
If this screenshot is readable it sheds some light on the speed you need to stay below in order to not set the code P0495.

Looks like you already have it working though.

Screenshot_20191020-110442.png
 

Mektek

Well-Known Member
So if keeping the output at below 1600rpm is the key, a simple 555 based circuit could output the required frequency. But with an Arduino we could do this and use it with a temperature sensor as a fan controller and to turn on the fans when the AC is running.
You could have a staged fan control - one fan runs if it's sufficient and then if the temp rises too much the second fan kicks in.
 

Mooseman

Moderator
I think it would be better noise wise to have a circuit that runs both fans at half and then at full when needed. I had done this in my efans setup and kept the noise down at half speed. It worked well except the fans couldn't cool enough.
 

rufusthedog

Member
So if keeping the output at below 1600rpm is the key, a simple 555 based circuit could output the required frequency. But with an Arduino we could do this and use it with a temperature sensor as a fan controller and to turn on the fans when the AC is running.
You could have a staged fan control - one fan runs if it's sufficient and then if the temp rises too much the second fan kicks in.
The 555 timer would work but AtTiny85 is so cheap and doesn't require any external parts other than a 5V regulator. I decided the Occam's razor approach where the simplest solution is often the best and I didn't monitor anything and just sent out a fixed signal. If I went with PWM fan I would have to monitor the temperature and adjust the PWM signal as required. If the temp sensor or the FET died the fan could fail. If the pulses fail I just get a CEL light but fan still works.
 

Blckshdw

Moderator
What kinda temperatures do you see? If you don't mind me asking.
 

rufusthedog

Member
What kinda temperatures do you see? If you don't mind me asking.
I'm using a 210 on / 195 off thermostat for the fan but I haven't read the real temperature but I will hook up the code reader and get some real numbers. I did monitor the requested fan speed and hung around the the 600 RPM range.
 

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