Turn signals help

[daveccpa]

Okay I've gotten the brake lights and tail lights are all working. Now onto the turn signals. I have none. I have power going to the flasher but none coming out. I've replaced it with a new one still nothing.

I bypassed the flasher and wired up directly. I have power at the contacts on the column as well as at the lights. So I'm thinking this must be a grounding issue. How does the flasher ground?

Also is there a ground wire on the steering column.

This is in a 59 truck.

[Wrenchbender Ret]

The flasher or the turn switch don't have to be grounded. If you put a jumper across the flasher terms. the respective lights should come on when you turn on the switch. You will need to take a test light & trace it.

[_Ogre]

a 2 wire flasher should be a closed circuit, when you run power to a light it heats up a bi-metal strip that breaks the circuit, cools quickly and makes the circuit again.
test the flasher with a light or meter, power in should equal power out.
led flashers have 3 wires; hot, ground and lights, they must be grounded to work.
led lights don't pull enough power to heat up the bi-metal strip



what type of indicator switch do you have?
i've had tf truck with no blinkers, add on blinkers and factory blinkers
most early tf trucks with blinkers had the signalstat 900 turn indicator switch, some were self canceling using a wheel on the switch that contacted the back of the steering wheel.
though i think in late 58 gm came out with a column switch built in more like the cars of the era.

all gm turn signal lights from the 50s thru the 00s wire the same way, most new harnesses (ezwire, painless) follow the same method.
no matter if you have signalstat 900 or an s10 column they all wire the same
the rear bulbs are double filament bulbs; the small filament is tail light, the bright filament is turn/brake.
there are 2 hot wires that feed the turn signal switch; 1 from the brake switch and 1 from the blinker.
depending on what position the indicator switch is in dictates whether your light is turn or stop light.

[daveccpa]

Thanks for the response. It's the factory turn signals. I've now gotten the fronts to work but the rears don't work. Their is power coming out of the column to the connectors and power going out of the connectors. Both the rear brake lights and tail lights work. So the is obviously a missing link between the cab and rear. Does the rear turn signal wires go thru the brake light switch? I'm thinking that is where my problem is?

[G&R's57GMC]

Power to the brake light switch flows through the switch when brakes applied then to the factory T/S switch then depending on switch position to the brake lights, or one brake light while the T/S flasher supplies the other brake light which then would flash.

I.E. T/S switch in center = both brake lights

T/S switch down = left brake light flashing and right brake light on.

T/S switch up = right brake light flashing and left brake light on.


Meanwhile the front signal light would be doing this :

T/S switch in center = front signal lights off.

T/S switch down = left front sig. light flashing.

T/S switch up = right sig. light flashing.

Power from a switched source flows through the flasher to the T/S switch then flashes the selected lights.

[daveccpa]

Found the problem. The wires under the truck where hacked up and the rear turn signals where not connected. I haven't solved the problem yet as I've got some more work to do but at least I know why they don't work right. I may just have to buy a new wiring harness or run new rear wires.

[_Ogre]

Originally Posted by daveccpa

Both the rear brake lights and tail lights work. So the is obviously a missing link between the cab and rear. Does the rear turn signal wires go thru the brake light switch? I'm thinking that is where my problem is?

Originally Posted by daveccpa

Found the problem. The wires under the truck where hacked up and the rear turn signals where not connected.

you have not found the problem, your rear turn signals are hooked up if your brake lights work

back up and study the wiring diagram i posted.
your brake lights are your turn signals there are no additional wires.

i'll repeat that, your brake light are your turn signals

if your brake lights are working then there are no missing wires just missing connections.
the brake light switch feeds into the turn signal switch.
imo, you have the brake switch wired directly into the turn/stop lights and not into the turn signal switch

[daveccpa]

Ogre you are correct. I don't have them totally fixed but I have narrowed down the problem. Which is a long ways from where it was at a week ago. I haven't been able to look further at it today but it appears that they have four wires feeding the three in the back.

They had the tail light wire, a brake light wire coming from the front connected to the tail light wire and then to both sides stop lights. The two turn signal wires coming from the front harness where not connected properly to the rears. In fact they where not connected at all. It appears that for whatever reason they just added to brake light wire which I am assuming is connected to the stop light switch.

[mr48chev]

Someone probably just bypassed the turn signal switch to hook up brake lights in the past. Good to see that you got it figured out.

On a side note for others. on a rig where you use an aftermarket clamp on the column switch there are two styles of switches. The one that incorporates the brake lights lik the 900 series switch that Ogre showed above and the switches that require separate lights for stop and turn and those are often the ones you find on the column of the AD trucks that don't have the switch in the column and are the reason the trucks have extra turn signal lights mounted.

[_Ogre]

orrieg must be on sabbatical from the forum for a bit or he would have chipped in with his wiring diagram.
my 59 1 ton panel has the side marker lights that are common on the bigger trucks
but even those are hooked up to where 4 lights in back are used for stop/turn
looks like a freaking xmas tree from the back

[daveccpa]

All fixed now. They had the stop light switch wired wrong. It wasn't connected back to the turn signals. Thanks for all the help.

[_Ogre]

that's what we're here for, glad we could help