Turn Signal Flasher Help

[jonn6464]

Hey FABO!

I have also posted this question on a truck board, so apologies if you've seen it before.

I'm trying to understand the electrical path for my turn signal indicator lights on the dashboard.

I'm restoring a Plymouth truck and making a custom dash, so the original wiring/circuit board will not be used. I'm thinking about using turn signal indicators like this

When I trace the wire from the flasher (in the fuse block) it does not lead to the indicator lights (green arrows) in the original dash circuit board. Below, circled in RED is where the flasher wire goes, and circled in BLUE is the L&R indicator lights.

So, how does the indicator light (green arrow) on the dash know to flash instead of stay solid? Does the flasher wire go to the turn signal switch on the column and then to the L&R indicator light pins (BLUE circles)? Or something else?

Thank you for any replies.

 

[67Dart273]

I have almost zero documentation/ diagrams for trucks but here is how it works
The TS switch on the column is a magic box and does a LOT of stuff There are several inputs and outputs

So far as your indicators, read below, They are simply branched off the right and left front signal lamp wires coming out of the column TS switch

First, newer trucks will have the 4 way hazard switch incorporated into the column TS switch, older trucks will have a separate hazard switch, you might post what year your truck and if this is so

INPUTS (assuming hazard switch in the column TS switch):
1....Switched brake light power coming from the pedal switch, going into the TS switch
2....Full time "hot" power coming from the 4 way hazard flasher into the TS
3....Key switched turn flasher power coming from flasher, going into TS

OUTPUTS: (OUT of TS column switch, going to............)
1...Left rear signal/ brake lamp
2...Right rear signal/ brake lamp
3...Left front signal lamp--AND BRANCH OFF to panel and or fender indicator lamps
4...Right front signal lamp--AND branch off to panel and or fender indicator lamps

On older trucks with separate hazard switch, that switch setup is very special. The inputs are same as above EXCEPT no hazard flasher going to the column TS switch

On the external hazard switch, you have full time hot power feeding a flasher, and then going to the hazard switch. This is a 4 terminal switch, nothing is interconnected with switch off. With hazard flashers engaged, all 4 terminals are connected. The hazard flasher power goes to one terminal, and the other three feed off to.....front left signal, front right signal, and to the brake switch wire going into the column switch. The column switch must be centered and your foot OFF the brake for the hazards to flash. The flasher simply sends that power to all lights at once

HOW BRAKE LIGHTS WORK. The brake switch when pedal is applied, sends power into the column TS switch. With the switch centered, the switch routes the switched brake lights power to both rear signal lamps. With the TS in one turn position, the TS disconnects the lamp which should flash, connects that lamp to the flasher, along with the proper front one, and continues to route brake light power to the opposite rear lamp

 

[67Dart273]

When I trace the wire from the flasher (in the fuse block) it does not lead to the indicator lights (green arrows) in the original dash circuit board. Below, circled in RED is where the flasher wire goes, and circled in BLUE is the L&R indicator lights.
View attachment 1715886373

So, how does the indicator light (green arrow) on the dash know to flash instead of stay solid? Does the flasher wire go to the turn signal switch on the column and then to the L&R indicator light pins (BLUE circles)? Or something else?

Thank you for any replies.

What you have there IS NOT THE flasher. That which is pictured is the regulator/ limiter for the gauges. The flashers are hung loose under the dash, should be one for hazard and another for turn. The two indicator lamps simply are wired down and "somewhere" in the harness they branch into the front signal lamp wires for left and right front. This may be done right at the TS switch connector. I believe you are looking at tan and light green?

The flashers are not wired directly to the cluster at all. You either have the wrong wire, or a branch path as many fuses supply multiple loads. The wire you followed "may" have been switched power from the key to activate the cluster

 

[jonn6464]

What you have there IS NOT THE flasher. That which is pictured is the regulator/ limiter for the gauges. The flashers are hung loose under the dash, should be one for hazard and another for turn. The two indicator lamps simply are wired down and "somewhere" in the harness they branch into the front signal lamp wires for left and right front. This may be done right at the TS switch connector. I believe you are looking at tan and light green?

The flashers are not wired directly to the cluster at all. You either have the wrong wire, or a branch path as many fuses supply multiple loads. The wire you followed "may" have been switched power from the key to activate the cluster

Thanks for the detailed info. I believe I'm following your explanation.

Just a couple of things to clarify...

- This is a 1975 Plymouth Trailduster
- When I mentioned the flasher, I probably didn't explain it well, but they are in the fuse box located next to the glove box. Pics for reference

- There are 2 wires on the back of the T/Sig flasher. One (BLK/WHT) jumps to the fuse, then goes to pin C that I circled in red in my first post.
The other wire (RED) goes to the connector for the steering column. I believe you are saying that #2 RED comes from the T/Sig in the column to the flasher, then connects to #1 BLK/WHT which goes to the circuit board pin C.

I'm just hoping it works when I hook up the new TS indicators!

 

[67Dart273]

That has to be a mistake. You somehow got onto the wrong wire

The flasher basically gets power from a fuse that is switched ignition power so that I think all happens right in the box. The other wire would feed direct to the turn signal switch. There's some kind of partial pickup diagram over at MyMopar

I don't suppose you have an online link to a suitable manual that I can download?

Here is some stuff from the partial manual at MyMopar. Screenshot of the fuse panel. The red wire coming right side top, F3-18RE is the output of the flasher. It runs directly down to the TS connector at the column, 4th terminal down from the "pointy" end of the connector

 

[67Dart273]

Here is the download link for those diagrams. I'm not sure this is complete, but it does have the instrument panels stuff

https://mymopar.com/downloads/wiringdiagrams/79_Dodge_Truck_Wiring_Diagram.zip