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2005 chevy trailblazer_ls
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Discussion Starter #1
The 05 I6 blazer I have has an elusive problem. It started w/replacing my water pump. After changing it, I noticed that the fan roar became evident. I changed out the clutch, and no change. I have also replaced the fan clutch solid state relay. No change. Eureka, I found it -6 mos later! I had unbolted the red wire off the fuse block, not the mains connected to the large fuse, but the wire that connects to the right side of the fuse/relay center. I re-connected it thinking this must be it! Nope. No change. (I had disconnected it to replace my stuck open thermostat one week b4 I replaced the water pump). Yep left that wire off for the last 6 months. On top of that, my cruise control went from intermittently not turning on, to actually quitting during operation, to where it does not come on any more. I have a 4yr bs in auto tech, and this is killing me! Anyone willing to shoot me another idea? I have checked all brake lights-all good. a/c works good, and I have some info on fan operation. I can spin it easily by finger when cold and once the viscous putty is broken, it will freewheel for about 3 revs b4 stopping. Conversly, after hot operation, the fan is hard to spin and has no freewheeling action at all. Help, and I hope to be humbled by someone with great experience.

Sincerely, and truly frustrated.:confused:
 

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2004 gmc
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26,181 Posts
Do you have a SES code for fan overspeed? Pull the solid state relay and see if it still spins too fast. You could also have bent pin or abraded insulation short in the harness to the fan clutch so it's always overspeeding. If 12V shorts to the PWM input of the clutch that could do it.

Can you get a scan tool that will show you the actual fan RPM versus the commanded RPM?

Is your temp gauge on 210 all the time as expected?

A GM TechII tool can interrogate cruise control memory and see what the last few causes of the shutoff are - some are related to SES codes, and some are the control switch and brake light.

By "right" side do you mean the passenger side? That's a trailer power connector, and you wouldn't notice leaving it off, although most people don't even have it connected.

 

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2005 chevy trailblazer_ls
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Discussion Starter #3
Will investigate

The ses light does come on 90% of the time when at max rpm range. I will pull the relay and see if it still overspeeds/roars. I will use a scan tool as a last resort to check command /actual rpm-if nothing else turns up. 210 steady when reached. I was hoping the cruise might play into the symptom of the clutch behavior, but looks to be not. Yep trailer connector, good to know since it did not change any characteristics of any problems listed.

Thanks for the advice, I will check it out and post a reply.

Sincerely, BP.
 

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2005 chevy trailblazer_ls
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Discussion Starter #4
Fan clutch ramp up

Does a good fan clutch when not connected still roar under high rpm? Also how fast should I see the fan ramp up when engine is a couple of marks over the 210 mark? What I can do is stop the fan w/a rag (I have cut the shroud for access to the top of the fan) and slowing the fan is safe and easy to do. If the engine is hot i.e.:220, shouldn't it want to ramp that fan up relatively quickly? At this time, and that test, it took about a min to a min/half to speed up to an appreciable speed and moving some good air volume.-just seems slow, but I dont have a reference. My clutch has about 130K on it, and is the one the dealer replaced after the all too common gen 1 clutches. Note: when I had mentioned in the original thread that I had replaced the clutch and found no difference, I took it back to the parts dealer and put mine back in.

Sincerely, BP.
 

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2004 chevy trailblazer_ls_ext
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I have the same problems with the fan noise and speed on my 04 TB. Replaced the water pump because of grinding noise coming from the water pump hosing but did not have the fan clutch replaced (at the time the fan was operating properly and my temp was normal all the time). After the pump was replaced I noticed immediately that the fan was very loud and the truck would shake when the rpm were high. I return to the shop about the fan speed they said that the fan clutch was bad (even though it was fine the before they worked on it) I went ahead and had them replace the fan clutch. The fan noise was less but still not normal and now the service engine soon light is on. Took it to Auto Zone to have them read the codes P0495 and P0483 were stored multiple times. I will check the relay to see if that has any effect. Now I’m feeling pretty sure that the shop that worked on the truck screwed up the wiring or relay when they replaced the water pump! Will report back with findings thanks for the pictures!
 

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2005 chevy trailblazer_ls
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Same issue

I went to have my water pumped replaced and since that time the check engine light came on and the error codes are: P0495, P0483 and P0526.... I have not replaced the fan clutch yet but may be looking to do that this Sunday. I am curious to see if it may have been something with the relay when they put the water pump back in. Does anyone have a diagram of how the relay is supposed to be setup? Where can I located the relay?
 

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After my first post I have gone back to the shop FOUR TIMES each time they have put in a 'new' fan clutch. The last time I said that they need to put in a oem clutch, it is finally better. I'm not sure their parts supplier of the other clutches but they were all junk.
 
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