I recently opened my laptop to repair a faulty internal DC power jack, which involved removing and reinstalling the Broadcom wireless card. Wireless worked fine before but now I cannot locate any APs (wired internet works fine). I reconnected the antenna wires to I believe the correct attachment points on the wireless card and cannot determine what's wrong. Toggling the physical wireless button doesn't seem to make a difference (doesn't seem to affect the wireless LED either). Here are some diagnostics that might be helpful. Would be more than grateful to anyone who can help troubleshoot this problem. Does this seem like a hardware problem? The only thing that changed between the wireless working and not working was removing and reinstalling the wireless card...

# iwconfig
lo no wireless extensions.

eth0 no wireless extensions.

wmaster0 no wireless extensions.

wlan0 IEEE 802.11 ESSID:""
Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
Tx-Power=20 dBm
Retry min limit:7 RTS thrff Fragment thr=2352 B
Encryption keyff
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0

# iwlist wlan0 scan
wlan0 No scan results

# lspci | grep Broadcom
06:02.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)

# dmesg | grep b43
[ 10.649035] b43-phy0: Broadcom 4318 WLAN found
[ 21.179076] input: b43-phy0 as /class/input/input8
[ 21.260105] firmware: requesting b43/ucode5.fw
[ 21.382393] firmware: requesting b43/pcm5.fw
[ 21.459161] firmware: requesting b43/b0g0initvals5.fw
[ 21.488703] firmware: requesting b43/b0g0bsinitvals5.fw
[ 21.684073] b43-phy0: Loading firmware version 410.2160 (2007-05-26 15:32:10)
[ 22.628439] Registered led device: b43-phy0::radio
[ 22.628606] b43-phy0: Radio hardware status changed to DISABLED

# ifconfig wlan0 down
# ifconfig wlan0 up
# dmesg | tail
...
[ 972.063512] input: b43-phy0 as /class/input/input9
[ 972.300579] b43-phy0: Loading firmware version 410.2160 (2007-05-26 15:32:10)
[ 973.092472] Registered led device: b43-phy0::radio
[ 973.092575] b43-phy0: Radio hardware status changed to DISABLED
[ 973.188078] b43-phy0: Radio turned on by software
[ 973.188088] b43-phy0: The hardware RF-kill button still turns the radio physically off. Press the button to turn it on.
[ 973.188891] ADDRCONF(NETDEV_UP): wlan0: link is not ready

b43-phy0: Radio hardware status changed to DISABLED

Looks like you need to turn it on by your button. Check again, may be something happened with physical button?

Thanks - toggling the button doesn't seem to help. I suppose it's possible that there was a hardware glitch with the button itself such that it became locked in the off position. Would there be a way to completely disable the hardware wireless button? I'd rather not use it at all and control the wireless card with the software. Here's are the messages I get from hitting the button... Thanks again

<<LIGHT IS ON>>

# ifconfig wlan0 down

<<LIGHT TURNS OFF>>

# ifconfig wlan0 up

<<LIGHT REMAINS OFF>>

# dmesg | tail
[ 1233.452476] Registered led device: b43-phy0::radio
[ 1233.500090] b43-phy0: Radio hardware status changed to DISABLED
[ 1233.516675] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 4424.883910] input: b43-phy0 as /class/input/input11
[ 4425.088893] b43-phy0: Loading firmware version 410.2160 (2007-05-26 15:32:10)
[ 4425.896414] Registered led device: b43-phy0::radio
[ 4425.896496] b43-phy0: Radio hardware status changed to DISABLED
[ 4425.980063] b43-phy0: Radio turned on by software
[ 4425.980068] b43-phy0: The hardware RF-kill button still turns the radio physically off. Press the button to turn it on.
[ 4425.980564] ADDRCONF(NETDEV_UP): wlan0: link is not ready

<<I HIT THE BUTTON HERE>>

<<LIGHT REMAINS OFF>>

# ifconfig wlan0 down
# ifconfig wlan0 up

<<LIGHT TURNS ON>>

# dmesg | tail
[ 4425.896414] Registered led device: b43-phy0::radio
[ 4425.896496] b43-phy0: Radio hardware status changed to DISABLED
[ 4425.980063] b43-phy0: Radio turned on by software
[ 4425.980068] b43-phy0: The hardware RF-kill button still turns the radio physically off. Press the button to turn it on.
[ 4425.980564] ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 4464.050560] input: b43-phy0 as /class/input/input12
[ 4464.248045] b43-phy0: Loading firmware version 410.2160 (2007-05-26 15:32:10)
[ 4465.060471] Registered led device: b43-phy0::radio
[ 4465.108086] b43-phy0: Radio hardware status changed to DISABLED
[ 4465.124680] ADDRCONF(NETDEV_UP): wlan0: link is not ready

# iwlist wlan0 scan
wlan0 No scan results

SOLVED! For *some* reason, the wireless LAN had become disabled in the BIOS. Going into the BIOS setup when I restarted, I noticed that the "Embedded Wireless LAN" was set to "disabled". I set this to enabled and the wireless worked just as before. I hope this is helpful to others who have the same issue, since I couldn't find any answers to this issue on the forums.