Trying to Repurpose Wiper Switch

[pokey1416]

Since I don’t have or need a rear wiper I got the bright idea to use a rear wiper switch and it’s circuit for LED beacon. Thought the momentary “wash” could be used to change flash pattern. Spent the last day and a half and am stumped!

Removed roof, loosened headliner in back and pulled connector up on top. Thought I tested connector with wife operating switch and found 12V switched, ground, and momentary 12V. Cut off connector, wired up long pigtail to left side of roof using 3 of the 4 wires in connector. Tested and find that as soon as ignition is ON the beacon started flashing. I was able to change flash patterns by activating momentary “wash” (of course this also expelled washer fluid down back window). But no way to get flasher off unless ignition was off.

Got to be missing something or maybe it isn’t possible to accomplish what I thought. I’ve confirmed switch and harness are ok via WSM troubleshooting. Traced solid blue wire from top to 30A wiper fuse under dash - which explains constant 12V when ignition ON.

I’m lost and hoping someone can help. Here’s pics.

 

[chim]

CAUTION - wait for someone who really knows what's happening I'm a little lost, but maybe can get this started. It appears the front and rear wiper motors and front and rear washers are powered from a 30A fuse.

The switch provides a ground to run the wiper and washer (Terminal marked "W" for the washer).

Terminal marked "3" looks like some sort of pilot power that serves other controls as well, and may not have sufficient energy for a real load.

 

[Fordtech86]

I’m a few beers in,but I’ll take a swing

The Blue wire is constant power as you know, add a relay, use the blue constant for the load side and power to your switch side of the relay, use the green/black wire as the switch control (ground side) to activate the relay.

 

[pokey1416]

Oh my Chim and Fordtech86 you are awesome. I never thought about adding a relay! This is great info - thank you both so much.

 

[pokey1416]

Thought I'd update and basically close this thread. I could not get the wiper switch to work for my purposes, even with Chim and Fordtech86's help. I must have watched a hundred YT on relays. I think my problem is I'm trying to do everything after the switch anyways, I just wired the light into the front work lights and have a short pigtail I can plug in and touch to the chassis ground on the front worklight if I want to change patterns. Done in like 10 minutes.

Now, putting the roof back on after reflectix was a whole different story! Yikes.