ot but farm truck electrical geniouses needed

apoligize for sticking this here but i need help and this is my best shot, what im working on is a 1957 chevy 4400 farmtruck, the turn signals, im running new wires as the old spagetti mess was untracable it was so cut up and spliced, what i have is no flash, the turn signal switch itself seems to be working as its directing power to the seperate wires when one or the other direction is selected, the wireing is factory to the firewall, i have power to the flasher, but it wont flash unless i wire a lite to it and lay the lite [ one of the front turn signals off the fender] on the floor,of course it flashed both ways wired in right there, so where do i need to go to find the correct wires on the firewall inside the engine bay? i have the original 1957 factory shop manuel, the 2 inch thick 900 page manual, but it claims the turn signals are a option, and doesnt cover the wireing colors, these turn signals are not add on there intregal with the steering colume, any help is appreciated, ive diagnosed myself into a corner!
this truck is being semi restored, for its original owner who bought it new, and it has 39000 actual miles on it

If there is a bulkhead connector, the wires should be easy to follow through from inside to out. If not, a simple test light will flash when touched to the conductor of the signal wire where the bundle comes out. Optional signal systems may have their own through connector, but maybe not. If you pierce the insulation of a wire, use a bit of tape or dab of Goop sealer on the hole to prevent internal decay. Jim

(quoted from post at 11:42:54 12/23/13) apoligize for sticking this here but i need help and this is my best shot, what im working on is a 1957 chevy 4400 farmtruck, the turn signals, im running new wires as the old spagetti mess was untracable it was so cut up and spliced, what i have is no flash, the turn signal switch itself seems to be working as its directing power to the seperate wires when one or the other direction is selected, the wireing is factory to the firewall, i have power to the flasher, but it wont flash unless i wire a lite to it and lay the lite [ one of the front turn signals off the fender] on the floor,of course it flashed both ways wired in right there, so where do i need to go to find the correct wires on the firewall inside the engine bay? i have the original 1957 factory shop manuel, the 2 inch thick 900 page manual, but it claims the turn signals are a option, and doesnt cover the wireing colors, these turn signals are not add on there intregal with the steering colume, any help is appreciated, ive diagnosed myself into a corner!
this truck is being semi restored, for its original owner who bought it new, and it has 39000 actual miles on it

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Just a thought. Find where the wiring inside the cab goes through the firewall. There should be a large connector on the engine side of the firewall which can be unplugged. You could then use a test light to find the correct prong inside of that firewall plug, and then compare the location of that prong to the corresponding prong in the matching connector. Come to think of it, that firewall plug JUST MIGHT be where all the trouble is. Those things did have a tendency to corrode if any kind of moisture got in there.

You have 2 choices

1.) Go out a buy a universal aftermarket turn signal switch and clamp just below the steering wheel, The wire diagram that comes with the turn signal switch will tell you how to hook up everything. New wire to all the lights will save you a lot of trouble and make the job go faster.

2.) Spend a lot of time -- and I mean a lot of time -- figuring out the existing wiring. If it's all cut up and spliced the OEM wiring schematic may not help that much as you could have a lot of stuff rewired.

You'll have to use a trouble shooting light and some small jumpers to test everything out and then it may work only some of the time.

The intermittent problems will now start to show themselves that will drive you crazy and continue to going forward.

Been there done that -- I'd just go new with everything

I've got a 58 GMC that I use as the main straight truck here. It has integrated turn signals as well. The wiring should be the same and mine is original. Let me know what you want me to trace or take pictures of.

Mine flash good but I have always thought they were a little fast. I'm not about to mess with them, though. Sounds like I shouldn't be looking a gift horse in the mouth.

what i need to know i guess is on the drivers side of the firewall this one has 2 sets of wires comming out of the firewall one had 5 or 6 and is about a half inch in diameter and goes down to a factory plastic connestor, the other is just 2 wires, it comes out the same hole in the firewall, and has 2 a lite green with blue stripe and a dark blue, im trying to find out which of them is turn signal wires, there is also a pale green wire on the other wire set which has been spliced, and cut,but the manual shows that color going to the headlites , if i can just find out which color wires the turn signals are i can go from there, i have a new wire set running from the firewall to the back lites now, but i dont want to wire up into the turnsignal on the colum or ill have the front signals comming on with the brake lites, somewhere under there there is a switch which prevents that and i want to stay under the hood, downstream from that switch

notjustair:

If your flashers are fast, CAREFULLY use an ice-pick to poke 3 or 4 holes in the flasher can, it will slow the flash rate. Don't ask me why this works, but it does.

Doc

I will go out and look in a bit. I know that on mine there are brake lights and then there are turn signals. Two separate fixtures. The brake light (only one originally) is on the tag side of the frame rail. The turn signals are mounted to the bottom of the grain box even with the end of the frame rail. Mine came like that originally - mine is a low mileage original as well. I have replaced many of those old lights as the metal frame on them has rotted out over the years. The round turn signals on the back doubled as the tail lights so that is how the brakes and turn signals were separated. They went to different fixtures. The turn signal fixtures were a two wire fixture. When I replaced the brake light I put in another one to have two and wired those in as tail lights also. I now have four tail lights on mine.

Keep checking back. I will put the coveralls back on again shortly.

The brake light wire goes though the signal switch in the column when you turn a signal on it separates the brake from the signal for that side only. It's all done within the switch. There should be four wires coming from the switch in the column that go to each light. When the signal is off the two to the back are brake only. Turn the signal switch to one side or the other and it shuts the brake light off for that side and let's the light flash. You need to go to the wires coming from the column to see which is which. Use a test light to check as you work the system.
Walt

Ok, I looked at my truck closely. Here's what happens:

A red power wire goes into the round flasher relay and a yellow comes out of it. That yellow runs up the column to the signal switch. A dark blue and a light blue leave that switch and go back down the column. There is a connector and then they run through the firewall using the same hole as the speedo cable. They are still dark and light blue. Right under the hole there is a large connector (probably 6 wires). They are still dark and light blue when they leave the connector but a dark and light blue branch off and go toward the rear of the truck. AT NO TIME IS THE BRAKE CIRCUIT ANY PART OF THE TURN SIGNAL CIRCUIT. The brake circuit is a simple power wire to the switch and then a wire to the light. It never enters the cab.

After this branch off at the connector the two blues run to the front radiator support where they tie into the signals. Dark blue is right side signals and light blue is left signals.

So, to answer your question, if you are tying the turn signal and brake lights into a common rear housing you are going to need to design a circuit yourself. They originally went to two separate light housings, thus the reason they can work independently.

I was wondering if your lights won't flash because they're not grounded. You said they won't flash unless you lay them on the floor. Or did I misunderstand your question ? Flashers have to send power thru a light to ground to work. To wire it you can use whatever color you want (semis always use green for right and yellow for left). And if your brake lights are separate your wiring will be easy = 1 color for both left and 1 color for right. With a test light, just put switch in left turn position, find the wire that blinks the test lamp, id it and do the same for the right and wire accordingly. Your test light will blink because you ground it. Always check your test light on a known good ground and probe on good known hot. Mark

Your fast flash comes from using a 4 or 6 bulb flasher. signals require a 2 buld flasher and 4 way flas requires a 4 bulb flasher. If you can't find, go to NAPA.
OR VICE A VERSA.

They flash fast when they heat fast. Holes allow them to stay cool and operate slower. A flasher is only a simple resetting breaker.

ok, thanks for looking for me i apreciate it a lot, what ive found is the truck has the exact setup yours has color wise, aparently its loosing something in the turn signal somewhere, as i have power in the dark blue wire on both sides of the signal, and no power on the light blue, i ordered a new turn signal switch tonite, we'll see if that gets it straitened out, this truck has set in a barn for 40 years and there must be a problem in the switch or id have power in the light blue wire on one side,and power on the dark blue on the other side , thanks again for all your help, this thing was making me crazy