How do you replace the fan clutch wiring harness on a 2003 trailblazer?

Answer 1

Just did this myself on my 2002 TB.

Not sure how old your question is... but for future reference (since I don't see any other related help out there for this thing, most people just change out the entire fan clutch):

Step 1:

Loosen the bolts that attach the Radiator Fan to the Fan Clutch.

So... you're standing in front of the vehicle, looking down at the engine.

There are 4 bolts. It doesn't take much to loosen them, and then pull them out by hand. Put them in a safe place. (Sip a beer at this point)

This allows you to gently nudge the plastic fan blade assembly off the clutch and towards the engine. It's ok, it worked just fine. Just don't be rough with the fan blades, you don't want to break anything.

Step 2:

Loosen the bolts attaching the Fan Shroud to the Radiator Assembly.

Two bolts... notice in the middle of the shroud, there's a little thing that hooks onto the Radiator Assembly.

Once unbolted, you're going to have to shimmy and lift this shroud up and backwards into the same area that the fan blade is now resting. Towards the engine, and away from the Radiator.

(TRICK: Undo the Radiator Return Hose on the Left side, the big fat thing... you will lose some coolant, make sure there are no cats in the area. And wash the driveway down after you;'re done so you don't kill any kittens. I had it undone only long enough to work the shroud off. Then I hooked it all back up.)

WARNING:!!!!!!

THE RADIATOR IS NOW UNPROTECTED... EITHER COVER IT WITH CARDBOARD, OR BE SUPER CAREFUL. NO TOOLS CLOSE TO IT, OTHERWISE YOU'LL PUNCTURE IT AND HATE YOURSELF UNTIL NEXT PAYDAY. AND THEN HATE YOURSELF SOME MORE.

(Didn't actually do it, but I've read some nasty stories of folks screwing up here)

STEP 3:

You can now readily see the Fan Clutch Wiring Harness.

Mounted to this spindle arm, and the other end to the Fan Shroud.

Unhook the Fan Shroud side, and pop the plastic fastener that's securing it. I lost it in the engine, so I used a zip tie to resecure it later.There's two clips that also keep it secured, you can pinch those on the inside to loosen.

STEP 4:

Moving your attention to the Fan Clutch side of the harness.

You can move the spindle arm to get at the harness easier. NO big deal.

Carefully feed each individual wire that's on the Fan Clutch side through the slot on the spindle arm. Once that's done, you can yank the entire Harness out of there...

if you've been throwing codes and seeing the reduced power light, you'll notice that the wires are either frayed, or one of them has disconnected from the wire harness adapter all together.

STEP 5:

Reverse the process with your $100 brand spanking wire harness.

Getting the new one on is pretty quick, with the spindle arm slowing you down somewhat. Be careful here, you don't want to pull out any wires.

STEP 6:

Once your harness is attached and secured to both the Spindle Arm side and the Fan Shroud side, carefully remount everything.

STEP 7:

Breathe... take a swig of beer, you haven't screwed up the Radiator, and the hard parts are all but done.

The shroud show now be attached to the Radiator Assembly.

Align your Radiator Fan to the holes in the Fan Clutch. Hand feed, then tighten in cross pattern. DOn't over tighten. But make it secure.

STEP 8:

Remove all tools and recheck everything. Good? Done.

STEP 9:

Start your engine.

The Fan clutch will be engaged and you'll notice the airflow coming off the FAN.

This is normal.

Go to your OBD reader and clear your codes (Amazon, cheap...)

Close your hood.

Take a drive.

When your engine is at operating temp, you'll notice that you don't sound like a jet engine.

STEP 10:

after a short test drive... return home.

Wash your dirty grimy hands. Enjoy your beer.

Took me an hour and half to do this.