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Discussion Starter · #1 · (Edited)
Hello, If anyone has insight for this 2008 Impala... I was trying to narrow down a stuck fan noise (and a battery drain). Removed 3 out of 5 fan fuses and the noise continues. The last two are tricky. When I find it, was thinking of just removing the fuse from the problematic fan component and avoid the expensive repair. Fan fuses 30 and 30 below (denoted in red) don't seem as readily removable as the first 3 I removed; the green check marked fuses in the fan fuse row. Is there a special trick to their removal (the purple fuses)? Or are they related to engine cooling and should not be messed with? Can find little online on these fuses. Thanks!
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Those two are 30Amp JCASE fuses. They pull straight up out of the fuse block. Rock them slightly and they'll move.

The components you've checkmarked are not fuses. They're ISO 280 micro relays. The 1" gray cubes are ISO 280 mini relays. GM & Delphi sourced them from Omron and Tyco. Way cheaper to buy Omron and Tyco branded 4 & 5 terminal ISO 280 relays from Mouser, DigiKey, Newark, DelCity, ... and there's no difference in quality. I buy the 40Amp relays. They will fit in place of the 20A & 30A parts just fine. It was probably cheaper to buy several different lower amperage relays but there's no reason for us to bother. Not sure how much the pick a part guys get for em. Probably too much.

The ISO 280 micro relays you pulled out should drive the radiator fan and HVAC blower.
The 30A JCASE fuses are likely for the same circuits.

Now... I wouldn't pull those fuses and I would put those relays back where they belong.

If you have a fan running with the ignition off you need to find out which one it is and properly deal with it.
The HVAC blower will run for 30sec to a few minutes after you switch the ignition off. This is normal. Don't mess with the after-run on the HVAC blower. It runs to dry out the evaporator so L-Pneumophilla bacteria (Legionaires disease) among other nasty bacterias and molds don't have a moist warm environment to grow in the HVAC system of your car. Best case the HVAC will stink like damp musty laundry or a moldy HE clothes washer that's not taken care of... worst case you get a case of lethal pneumonia from the AC in your car.

If it's the radiator fans... again they will run for up to a few minutes after you go for a toot so the engine doesn't heat soak and blow gaskets.
 

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Discussion Starter · #3 ·
Thanks for the insight! I appreciate it. I do have a fan that is stuck and makes a jackhammer noise with or without keys in the ignition (louder the more charged the battery is, implying battery drain when parked for a bit). What is the best way to "find out which one it is and properly deal with it"? Is the fuse narrowing the way to go, but only temporarily leaving one out?'
Thanks!
 

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Jackhammering noise from under the dash is usually blend door motors. Less often it's the recirc door motor.

You can temporarily unplug them to shut them up.
You'll find several threads about how to deal with them.
 
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This video has the jackhammering blend door actuator noise starting around 1:18
 
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