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Did you mess with the fan clutch? Thats the code for the PCM not seeing a signal from the fan clutch, if you've swapped it for efans then it should be on or your wiring harness is messed up.
 

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2002 chevy trailblazer_lt
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Trailblazer Fan Clutch and P1481/P1482

Did a lot of reading on this forum and spent several hours trying to solve my 2002 TB fan clutch issues and thought I'd share my experience.

First, I started out getting the high fan speed code, sorry don't recall the code number off the top of my head, but based on what I read I ordered a replacement fan clutch from ebay. Installed the new clutch fan and the high fan speed code was gone, but then I had P1481, no fan speed detection. Pulled the unit back off and checked all the wires and connectors, put it back on, same thing. Finally I took it off again and compared the wiring harness with the original one by tracing the wires from the connector on one end to the other. To my surprise, and much excitement I might add, found two of the wires on the after market unit were swapped at one of the connectors. Anyway, corrected that and put it back on, then I was getting P1482, *@&%!. Ended up pulling if off again, very frustrated at this point, didn't really see anything, so I unscrewed the sensor from the clutch assembly itself and swapped the original one for the replacement one and put it back on, still had P1482.

At this point I finally decided to look for other things and found the fuse was blown (No. 20 in the fuse box on the driver's fender well). Apparently, the instant I turned the vehicle on with the replacement unit, the one that had the wires swapped, it shorted the circuit and blew the fuse. So, all the other work I did was for nothing, it was the blown fuse due to the swapped wires. So, if you have a similar problem be sure to trace out the wires on your new unit and if you've already installed it, check the fuse! What an ordeal, but no light now and the fan works great!
 

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So I have a 02 trailblazer LT with the 4.2l i6 motor I have just scan my truck to find a p1482 code I have checked the fuse it's fan clutch recently replaced with another 02 fan clutch so wiring harness and all should be exactly the same the harness is in great condition wires intact no vision damage of chafing or dry rotting the relay is the only thing I haven't checked but my fan is not roaring so that from what I read is a sign that the control and speed are fine the fan follows the rpm as it should I do not have the tools or scanners to search down my cause for it all of this is vision physical and sound based the only thing I can think is causing this problem is the connectors between the fuse fan and radiation again dont think that's the cause do to the fact my fan is functioning as it should I'm thinking that this is probably a soft code that my obd2 scanner can pick up cause of have to codes for the catalyst both are exactly the same codes talking to a certified and retired mechanic he said one is a soft code and ones a hard code more then likely if there is something I have missed checking in the process please mention (anything regarding the catalyst my truck is straight pipe it has no catalytic converter or leak just encase someone mention the catalyst as my problem) so I just want to cover all my bases regarding the 1482 code I have never seen this code until today but my fan is not showing any functionality problems as of yet if no one can think of anything I will clear the codes and drive it to see if it was just a soft code or not
 

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Please , could you use punctuation ?
I got a couple lines in and quit . :(
It irks me too.... I bet there's a really good question somewhere inside that alphabet soup... and I'd like to help... but it's tedious to copy/paste the one-big-paragraph into legible and cohesive thoughts.

I give up on reading any questions without AT LEAST one period or capitolization .....somewhere....

Many times I break each sentence into a new paragraph to make my writing easier to comprehend.

I even use my trademark Triple Dots as commas ... just to break continuity.
 

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Please , could you use punctuation ?
I got a couple lines in and quit . :(
To assist with the jumbled mess I have done everything I know to look for on my trailblazer that is related to the fan clutch I do not have the tools or scanners to check the electrical, but everything works as it should so that is where I am at on this my obd2 scanner has given me a hard code for this problem now and I am having overheating issues with it
 

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It irks me too.... I bet there's a really good question somewhere inside that alphabet soup... and I'd like to help... but it's tedious to copy/paste the one-big-paragraph into legible and cohesive thoughts.

I give up on reading any questions without AT LEAST one period or capitolization .....somewhere....

Many times I break each sentence into a new paragraph to make my writing easier to comprehend.

I even use my trademark Triple Dots as commas ... just to break continuity.
To assist with the jumbled mess I have check everything that I know to look for related to the fan clutch and everything appears to be working, but my obd2 scanner has pulled a hard code for the clutch p1482 to be exact. everything appears fine and as it should but I am having an over heating issues which the thermostat is on the list for that I do not have the tools or scanners to test the electrical pieces of this so if it's a connection issues I wont be able to find it exactly
 

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2002 chevy trailblazer_lt
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If I am reading your questions right.... did you already replace the fan clutch? If yes, was that just recently or some time ago?

Please describe your "overheating issues" in some detail. Is there steam coming out somewhere? Are there warning lights? What does the dashboard engine temperature gauge read?
 

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2002 chevy trailblazer_lt
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Here is something easy you can try,,, swap #45 & #46 in the underhood fusebox. They are the same part type. #45 is the solid state control relay for the engine cooling fan. #46 is for Daytime Running Lights (low beam headlights). Swapping them 'might' help to determine if the trouble is in the relay module.

2009-12-20_191446_atc_fuse.jpg
 

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The fan clutch yes has been replaced about 5 months ago I had to pull one from a yard so I found one that was in fairly decent condition I couldn't afford to shell out 250 for parts.


The over heating occurs at idle I drive about 45 minutes on the interstate and my truck stays at 210 the whole way when I get in town and stop at a red light for longer than 3 minutes the temp starts to climb last night had a different scenario though driving home doing 55 on a hwy the temp kept climbing all the way up to 260 I pulled over stopped and open the hood to cool it off no steam or leaks anywhere but the system was under more pressure than usual


The truck doesnt over heat as long as the motor is spinning at at least 1000 rpm cause of the increase water flow but this recent event has made me start looking at the thermostat the gauge would fluctuate between 210 and 230 the odd part about it was that was happening while the motor was spinning at the 1000 rpm or more and not at lights like it usually does I do not have a code for the thermostat the truck has almost 317k miles on it all fluids are changed on the regular and maintenance is kept up until the recent shutdown my hours are all screwed up so I haven't had the money to do all these repairs.


New water pump is in place and just to be safe I swapped the fuse it didnt look blown but swapped it in case it was faulty no changes have happened yet. radiator has water and coolant.
 

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I will give it a try and see if that may do the trick if it does it will save me about 250 in labor and another 100 in buying another amazon has great deals on them and have a form for you to fill out to insure the fit haven't gone wrong yet beats autozone 250 for it
 

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I also have a 2002 and I also have pulled fan clutch from a scrapyard. In my case the one from the scrapyard also doesn't work quite right. So the one you got from scrapyard can also be bad.

When you were overheating and had the hood open....did the cooling fan seem to be making more noise than normal? I am going to guess that it was not. There should be a noticeable difference in the sound the fan makes when the engine is overheating. It really will make a hell of a lot more noise.
Maybe I can make a short video to demonstrate that!
 

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If I am reading your questions right.... did you already replace the fan clutch? If yes, was that just recently or some time ago?

Please describe your "overheating issues" in some detail. Is there steam coming out
I also have a 2002 and I also have pulled fan clutch from a scrapyard. In my case the one from the scrapyard also doesn't work quite right. So the one you got from scrapyard can also be bad.

When you were overheating and had the hood open....did the cooling fan seem to be making more noise than normal? I am going to guess that it was not. There should be a noticeable difference in the sound the fan makes when the engine is overheating. It really will make a hell of a lot more noise.
Maybe I can make a short video to demonstrate that!
It wasnt making more noise than normal that roar is very distinctive there was no steam no leaks from looking at it I avoided any damage when I stopped if the engine temp gauge was correct it was running 260 the gauge had fluctuated last night while I was driving no code for the thermostat either just fan and catalyst (my truck doesnt have a catalytic converter it has been straight piped) it would not surprise me if the clutch I got from the yard died or was no good it was another 02 clutch I have a new clutch ordered for it with a return policy if I dont need it
somewhere? Are there warning lights? What does the dashboard engine temperature gauge read?
 

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"Overheating" is technically when you are losing coolant and it's hitting the ground.

I question the accuracy of the temperature gauge here since you have not actually answered the questions posed by other members. You seem to be set on believing that the engine is actually overheating.

USED parts from a junkyard are always suspect and since you already have a used fan clutch - I wouldn't put too much faith in another used one - not even a 'gently used' one.

You need to get a real temperature reading somehow - and remember that this cooling system is an orphan in design and it isn't going to work like most any others. The thermostat regulates the coolant going INTO the engine, not to the radiator.

The reason why the temp is regulated into the engine is because this engine operates correctly in a very narrow temperature band.

It is almost all aluminum and correct expansion rates of the nonferrous metal parts is very important.

A decent test for correct fan operation is to turn the AC ON and let the engine idle. This will activate the cooling fan and you can tell if it's operating correctly - or at all - by the amount of air it pumps through the condenser and radiator.

Still - the best thing is to NOT believe the gauge - or even the computer's own CTS since they are suspect at this time anyway.

Beg-borrow-steal a non-contact infrared thermometer - Harbor Fright has them on the cheap - and every person needs one anyway.

Here's a couple of rules:

Engine getting hotter than normal at highway speeds is usually from poor circulation through the radiator/engine.

Caused by: partially closed thermostat, badly contaminated radiator core, lost coolant pump fins (it happens), slipping belt(s) - not so much, weak or inoperative thermal fan switch/clutch/ECU command, low coolant level, defective radiator cap (in your situation, it might have a cracked or missing o-ring).​
What NOT to believe --- or believe IN:
The level of coolant in the "recovery bottle" (which it is NOT) is not a true indicator of the actual amount of coolant in the engine or the radiator. If it's full - the engine may not have a drop of coolant in it. Beware of false assumptions.​
Don't EVEN think of an air bubble somewhere in the system: it would purge itself almost instantly once the thermostat opened anyway. BESIDES: you do NOT have one of those hard-to-prime cooling systems - not in the classical way, at least!​
Percentage of coolant to water is somewhat important; but for testing values - it's not a big problem here.

Get the real temperature and report back. Your radiator hoses may be cool to the touch (especially the one on the passenger's side) - and this is normal under many operating conditions for this engine.

If you can get heat from your heater system, then you should have sufficient coolant in the system - but check the level INSIDE THE RADIATOR NECK when it's cold.
 
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