Cheap and clever homemade turn signal switch.

Front turn signals not working on F250. I replaced them with sealed LED amber trailer lights that allow for both parking light and turn signal function.

Then found the OEM switch on column not good, you have to jiggle it to get right side signals to flash. Contacts worn out.

I found this really clever turn signal circuit using four 5-terminal Bosch relays. I am not claiming credit for its design and sorry cant find source I got it from (downloaded diagram to my computer some years back) or would give credit where its due, though similar circuit two or three places on web and one company actually selling this design in kit for crazy amount money(for the really lazy). So perhaps actual initial inventer lost to history. Seriously this is pretty simple to build though suggest strongly you use roll tape and a sharpie to label all connections, can get very confusing if you dont. Especially if you arent using color coded wires. Shop around and you can get new relays around $2 each on ebay though probably means waiting on slow boat from china. Want the ones that come with wired sockets that the relay plugs into. If you are really cheap, of course you can salvage them out of old cars. VEry rarely wear out and used for lot of things on modern cars.

It works very nicely, better than the cheap aftermarket turn signal switches that clamp to steering column or using a toggle switch with one of those trailer light converter boxes. And lot cheaper than either.

Be aware there are a LOT of connections to keep straight. Now for turn signal switch you can use a three position toggle switch or even wire into existing column turn signal switch if there is at least one good contact left on each side. It will just act like a toggle switch, the relays will do the heavy lifting.

I actually wired it both ways so have toggle on dash and the old turn signal switch. I did it this way cause the old switch was still pretty hit or miss whether it works, the contacts on right side are bad, though it still does self cancel. A toggle switch wont. By having it wired both ways, you can use either switch, though only if the other switch is in neutral middle off position. Oddly I found myself using the toggle switch mounted on dash more often than the old column switch. Mostly cause column switch is kinda flaky. the toggle switch is brand new and just works.

And looked like it should work, also added a two pole toggle switch so I also have four way emergency flashers from same circuit. That worked too. First time in long time this old truck has had functional emergency flashers.

Now I also fought with flasher can being able to flash LED lights. Mine was electronic, not the old thermal kind of can. Yet it still didnt flash left side correctly with LED. But it flashed right side ok. Because right side still had incandescent indicator bulb on dash. Indicator bulb on left missing and no socket for it. So I soldered marker light socket from an old GM car to left side, installed bulb, and it flashes fine now too. Probably better to solder resistors in, modern incandescent bulbs tend to be both expensive and short lived.

I had ordered two piezo buzzers from China for like $1.20 shipped with intention of wiring them into circuit. Day I got them also got another flasher can I had ordered from China for $1.36 or something. It supposedly made a loud beep. Not expecting much since flasher cans locally are over $10 now for plain jane variety. But plugged it in, and swear everybody at stop light probably going to hear it, it sounded like one of those truck backup warning buzzers. Assume it had one of those electronic buzzers built in. You arent going to ignore it and go happily down hiway with your turn signal on. Unless you are stone deaf.



www.ebay.com/itm/152003068434?

Notice the little hole in top. Well if you put a bit of tape over it, quiets it down a lot. I found this made it too quiet so I poked a pin hole in the tape over the hole in the flasher can. This seems to make sound just right for my preferences. Enough so its loud in truck cab without everybody at traffic light hearing it too.

No idea how long this will last but for the money even year or two and it earned its keep.