# ExplorerHAT Pro blue LED not working

**URL:** <https://forums.pimoroni.com/t/explorerhat-pro-blue-led-not-working/8133>\
**Category:** Support\
**Created:** [July 13, 2018, 4:49pm UTC](https://forums.pimoroni.com/t/explorerhat-pro-blue-led-not-working/8133 "2018-07-13T16:49:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![nate](https://avatars.discourse-cdn.com/v4/letter/n/e95f7d/32.png) [@nate](https://forums.pimoroni.com/u/nate)\
**Post date:** [July 13, 2018, 4:49pm UTC](https://forums.pimoroni.com/t/explorerhat-pro-blue-led-not-working/8133/1 "2018-07-13T16:49:26Z")

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Hello, I could use some help solving this issue.

**Problem**  
Blue LED does not work, while the red, yellow, and green LEDs work as expected. Most of the time the blue LED just doesn’t work at all when calling explorerhat.light.on(). Occasionally it will dimly turn on just once but then subsequent explorer.light.on() will not turn on. Also, when calling explorerhat.light.pulse() I can see that it intermittently flickers but at a very low level.

**Setup**  
RaspberryPi 3 Model B v1.2  
Wall adaptor power supply (stock from Adafruit)

(ENV) pi@raspberrypi:~/Software $ pip show explorerhat  
Name: ExplorerHAT  
Version: 0.4.2

(ENV) pi@raspberrypi:~/Software $ pip show RPi.GPIO  
Name: RPi.GPIO  
Version: 0.6.3

(ENV) pi@raspberrypi:~/Software $ less /etc/modules

```bash
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

i2c-dev

```

**Tried these from the forum without success:**

- [[Solved]ExplorerHAT Pro Blue LED failure](https://forums.pimoroni.com/t/solved-explorerhat-pro-blue-led-failure/1374)
- [Explorer HAT Pro lights flicker constantly after second s/w install](https://forums.pimoroni.com/t/explorer-hat-pro-lights-flicker-constantly-after-second-s-w-install/1850/3)
- /explorer-hat-pro-flickering-light-when-i-turn-it-on-using-flask-endpoint/5910

**Out of ideas, any thoughts?**  
I don’t think it is a HW issues (e.g. bad soldering) since there is some blue light activity. I have no other processes or jobs running. I am simply using python on the command line to import explorerhat and make the API calls.

Thanks in advance!

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**Author:** ![gadgetoid](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.pimoroni.com/gadgetoid/32/13_2.png) [@gadgetoid](https://forums.pimoroni.com/u/gadgetoid)\
**Post date:** [July 14, 2018, 12:31pm UTC](https://forums.pimoroni.com/t/explorerhat-pro-blue-led-not-working/8133/2 "2018-07-14T12:31:34Z")

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Have you tried checking and disabling the 1-wire interface on your Pi with `raspi-config` or the Raspberry Pi Configuration tool? It uses BCM4 by default and is by far the most common cause of this kind of weirdness.

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<div class="post-metadata">

**Author:** ![nate](https://avatars.discourse-cdn.com/v4/letter/n/e95f7d/32.png) [@nate](https://forums.pimoroni.com/u/nate)\
**Post date:** [July 17, 2018, 3:47am UTC](https://forums.pimoroni.com/t/explorerhat-pro-blue-led-not-working/8133/3 "2018-07-17T03:47:55Z")

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Thanks, that solved the issue.