Car fan keeps running even after the ignition is off

[H.G.P.]

Old Buick GM, fan keeps running after car shut off. Had to pull the fuse otherwise battery would be dead.

Pulled relays....fan still runs with car off.

Only pulling the AC blower fuse does the fan shut off.

Parts company says possibly blower resistor.

Question: Can I bypass this fuse and use a toggle switch without meltdown?

Thanks!

[fastfredracing]

Don't bypass the fuse, but put the switch after it, or at least use an inline fuse. In theory, there should be no power available to the blower motor resistor after the ignition is turned off.
I swear I have ran into this before, but I cannot recall what the fix was. Does this car have auto climate control, or manual?

[myamoto1]

Could be a shot temp sensor. I had the same issue on a Black Magic fan. Issue was resolved once I fixed the temp sensor.

[H.G.P.]

Originally Posted by fastfredracing

Don't bypass the fuse, but put the switch after it, or at least use an inline fuse. In theory, there should be no power available to the blower motor resistor after the ignition is turned off.
I swear I have ran into this before, but I cannot recall what the fix was. Does this car have auto climate control, or manual?

It has climate control (press the button for temp desired).... manual?
and climate control selection on passenger side also.

All the buttons work, including the desired temperature selection, however the fan runs on full/maximum for all of them......AC, heater, econ, dual climate.

[H.G.P.]

Originally Posted by myamoto1

Could be a shot temp sensor. I had the same issue on a Black Magic fan. Issue was resolved once I fixed the temp sensor.

Maintains correct temperature with the push buttton selection, just the fan keeps working at near max.

[H.G.P.]

Originally Posted by fastfredracing

In theory, there should be no power available to the blower motor resistor after the ignition is turned off.

I pulled each relay one by one and the fan kept running max with ignition off.

Only by pulling the green fuse i nthe engine compartment does the fan turn off.

I'm uncertain where the wiring goes after the fuse through the firewall or what to look for when it enters somewhere in the passenger compartment (under the seat?)

[porsche4life]

Sounds like a temp sensor.....

[red-beard]

One of my cars had a fan which would continue to cycle after the ignition was off. It was either the Honda Accord or the Jeep Cherokee.

[Heel n Toe]

H.G.P., you are talking about the fan in the dash, right?

Just trying to make absolutely certain you're not talking about the electric fan that pulls/pushes air through the radiator. Many of those tend to run for awhile even after the ignition is off... for good reason.

I've never known a car that has that fan and the dash fan on the same fuse, so... like I said, just checking.

[Zeke]

Or it could be a fault in the BCM (body control module). Run a fault check using the AC buttons.

No, I don't remember how the sequence works, but here are the instructions:
"To enter diagnostic mode:
Turn ignition "ON."
Depress the "OFF" and "WARMER" buttons on the Climate Control Center (CCC) simultaneously and hold until the segment check appears on the Instrument Panel Cluster (IPC)."

From here.