Adding manual fan switch

[smorgan87]

I know ive seen the posts about adding a manual fan control switch to one these prostars but i cant seem to find it. Same process as other trucks or is there an easier way that doesnt involve plumbing air lines and new relays and solonoids? I would like to fan on while idling and in traffic so the ac runs a bit cooler. Its factory head psi set point is a bit high. Thanks