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2003 chevy trailblazer_lt
6 Posts
Discussion Starter · #1 ·
So I have been doing my research on here and was wondering a couple things.
First thing:
What part exactly is the wirig harness? Is it on the cooling fan assembly itself or is it the wires that connect to the fan clutch in the engine bay? this is what throws me out the most.

Second thing:
Is there a thread that shows pic for pic on how to do this? I basically found this which is enough information for me to do it ( once I find out what the wiring harness is) but I am a visual learner so that would help alot. Here's a

TSB on the issue:

#05-06-02-012B: Service Engine Soon (SES) or Check Engine Light On, DTC P0480,
P0526/P1481/P1484 Set (Replace Engine Cooling Fan Wiring Harness) - (Oct 19, 2006)

Service Engine Soon (SES) or Check Engine Light On, DTC
P0480/P0526/P1481/P1484 Set (Replace Engine Cooling Fan
Wiring Harness)

2004-2006 Buick Rainier
2002-2006 Chevrolet TrailBlazer, TrailBlazer EXT
2002-2006 GMC Envoy, Envoy XL
2004-2005 GMC Envoy XUV
2005-2006 GMC Envoy Denali, Envoy XL Denali
2002-2004 Oldsmobile Bravada
2005-2006 Saab 9-7X


This bulletin is being revised to add DTC P1484. Please discard Corporate Bulletin Number 05-06-02-012A (Section 06 Engine/Propulsion System).


Some customers may comment that the Service Engine Soon (SES) or Check Engine light is illuminated. This condition may be intermittent and upon investigation, the technician may find either DTC P0480, P0526, P1481 or P1484 set.

This condition may be caused by the cooling fan harness chaffing against the plastic guide it routes through. This contact may damage the insulation of the wires enclosed in that harness.
Replace the engine cooling fan harness using the procedure listed below.

Remove the cooling fan. Refer to the Cooling Fan and Shroud Replacement procedure in the Engine Cooling sub-section of SI.
Place the cooling fan assembly on a bench.
Disconnect the harness electrical connector from the cooling fan clutch.
Remove the harness from the plastic guide while feeding the wires out of the slot.
Before installing the new harness, wrap the affected area on the wires with electrical tape to keep the protective sleeve in place. Be sure to keep the tape approximately 25 mm (1 in) away from the connector so the wires can be fed into the slot.
Feed the wires into the slot and install the harness to the plastic guide.
Connect the harness electrical connector to the cooling fan clutch.
Install the cooling fan. Refer to the Cooling Fan and Shroud Replacement procedure in the Engine Cooling sub-section of SI.

Parts Information

Part Number



Harness Assembly, Engine Cooling Fan Wiring

Third thing:
Does anybody know what the part is officially called? Cooling fan wiring harness? and the part number of the harness and where I can find one cheap.

These 3 questions if anwsered would help me out SOOO much and i can finally fix this pain in the butt problem.
up next i need a new tccm, new shocks, new upper control arm bushings, new windshield, new tires... ect lol
thanks guys,
you guys are always alot of help.

2003 chevy trailblazer_lt
6 Posts
Discussion Starter · #2 ·
Another thing I forgot to mention

I bought a new fan clutch about 6 months ago. I was wondering if that would go bad and need to buy a new fan clutch or just the wiring.

2005 chevy trailblazer_ls
1 Posts
05 tb p0641

So, I bought this 05 about a year ago... Maybe 3weeks after purchase the check engine light comes on... In October the a/c compressor seized up on me, which they tell me isn't covered on my warranty... �� I replace it and the check engine Stays on for the better part of the year... I scanned the codes and came back p0526 or whatever the fan speed sensor code is... So I'm thinking fan clutch... I've had the thing out 3 times now, never noticed anything... Today the REP light comes on (reduced engine power)... So I limped 10mph back to the house... I do all kind of research on p0641, which is the code it thru today... Good power to the tps, good power to all the sensors on the 5v reference circuit... So I pull the clutch and shroud and find that the horse**** dealership just put a piece of rubber fuel line over the wire harness going to the fan clutch, which had been previously rubbed thru and that 3 of the wires were severed completely... Thanks j.d. Byrider... You ****ing *******s... Anyway, this is my first tb/envoy... I like Chevy, but this thing has been nothing but problems... Until today I would just scroll thru the threads and find what I needed... Today I registered and I would like to personally thank all of you that post on here, you have saved me some money by having a free troubleshooting forum... You guys rock... Also, p0641, on mine, was the open circuit on the fan clutch wiring harness... Just a heads up... The dealership and shops will try to sell you a tps, or app (accelerator pedal position sensor) but the problem is that all of these things run on the same circuit... Good place to start is to check these wires... I'll let you know if it solves the REP situation...
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