Vcgencmd display_power o not working in crontab

I am running the latest version of OSMC on a Pi 3 B+ and I can not get ‘vcgencmd display_power 0’ or ‘vcgrencmd display_power 1’ to working in crontab. If I run the command over ssh in terminal from my mac it works, the monitor will turn on or shut off. So the command does not seem to be the issue. In crontab if I change-

Turn Monitor On Weekdays 6am

0 6 * * 1-5 vcgencmd display_power 1

to

Turn Monitor On Weekdays 6am

0 6 * * 1-5 reboot

The Pi will reboot at 6am so crontab does not seem to be the issue.

Any help would be appreciated.

Did you try using complete paths to your commands?

No, I am still learning and I do not know what the complete path for this command is

which vcgencmd will give you the complete path to the command.

Thank you

Did using the complete path resolve the issue in cron?

Yes, thanks

Enjoy!