Hazards Blink, turn signals stay on - no blink

[togntime1]

1974 FJ40. Hazards work fine. When I activate my turn signal switch , the lights just light up and stay on. No flash. Arrows in the cluster do the same. My flasher is a rectangular box mounted up by the clutch assembly. It has a two wire connection. I ordered a new flasher, but that has a 3 wire connection. Do we think this is a flasher issue or otherwise?
Thanks,

 

[EStein]

I’m the last person to give advice but if the flasher is working for the hazards, doesn’t that mean it should work for the turn signals as well? I just went through this but it was only one side that would stay on. Hazards would work and the right side would flash. Ended up being a loose wire behind the headlight for the turn signal and a really bad ground out at the fender. Is it left and right turn signal that just goes on but doesn’t flash? Took me most of the day to fix mine but I was told to just start tracing wires and making sure all the grounds are good and no loose wires.

 

[thebigredrocker]

I bet you just need to clean up grounds. Front turn housing mounting bolt to fender, fender to frame, rear turn housing to frame, ect.

Be aware that the flasher is a CURRENT driven device. That means that it MUST have at least 1.3 amps of current flowing through it BEFORE it will flash. What this means to the end user is that at least TWO bulbs must be lit before there is enough current to cause the flasher to flash. That is why the Hazards almost always work as it turns on all four bulbs. The turn signal only flashes two bulbs.

So...
If your battery is low (below 12.5 volts)
Your harness has bad grounds at the lights (high resistance)
Your bulb sockets are corroded (high resistance)
Your bulbs are the wrong type (not enough current flow)
Your turn signal switch is dirty (high resistance)
Your connections between any of these are dirty (high resistance)
Your flasher relay is defective (very possible if OEM) CityRacer sells an NEW OEM replacement or you can order one of my LED flasher kits (you do not have to use LED bulbs if you don't want to. It will flash normal bulbs also)
Your flasher relay works but has dirty relay contacts (high resistance)

If any, all, or some of the above apply...Your turn signals will NOT flash!

These high resistances add up quickly. If there were no resistances in the turn signal circuit you would have battery voltage (+12.7 volts) AT THE LIGHTS! The voltage readings posted above show a lot of resistance in the circuit. Just think about the path the current must take to reach the rear turn bulb. The key switch contacts, the fuse block fuse contacts, the turn/hazard switch contacts, the flasher contacts and all the bullet connectors and wire it must pass through, then finally the bulb sockets contacts, and last the ground connection. If you would clean everyone of these areas properly, you should see that voltage go up.

Another thing about voltage: Incandescent bulbs are rated at battery voltage for their rated lumen output. The lower the voltage at the bulb, the dimmer the light. A bulb rated at 13.2 volts will be how much dimmer at 10 volts? This is why the headlight relay harnesses were invented: to get the voltage at the head lights as high as possible for the brightest lights.

OEM colors for turn signals
Green = Park
Green/Orange (early) or Green/Black (later) = LEFT Turn
Green/Yellow = Right Turn
Green/Blue = Turn switch to flasher (L) to bulbs
Green/White or Green/Red Flasher (B) +12V

 

[cruiserkreutz]

/\/\/\ This

 

[togntime1]

I'm curious why it would be a grounding issue if it flashes with the hazard but doesn't flash with the turn signal. Does that mean it's a grounding issue with the switch side?

 

[Cromagnon]

There is only one flasher that is used for all of the circuits, Left, Right and Hazard. If the flasher works for any one of the circuits you can rule out the flasher as being bad. Now for your symptoms. Left and Right circuits light up but do not flash. Hazards work normally. You do not have enough current going to the Left or Right flasher circuits, individually, to heat up the bi-metalic strip in the flasher unit to cause it to break the circuit, cool off and make the circuit and repeating the cycle until you turn the circuit off. When you use the hazard circuit you have twice the current (both the Left and Right at the same time) to cause the flasher to operate.

The common failure point for the affected circuits are the grounds, as stated previously. With over 30 years as an electronics technician and 15 years as a EE, anytime I see an anomalous behavior in a circuit I check the grounds first. Saves a bunch of time and headache.

 

[3_puppies]

does it happen with both left and right turn?
have you checked the lights outside?
if a bulb is burned out, it won't flash.

 

[RWBeringer4x4]

My truck did this exact thing when I first bought it, and I asked a lot of the same questions (ie: If the hazards work, why don't the turn signals?). I never did get an answer, but adding ground wires at the individual turn signals solved the issue. instead of grounding to the metal body through the turn signal stalk, I drilled a small sheet metal screw into the metal back of the light housing, connected a ground wire to the screw with a ring terminal, ran the wire back into the engine bay with the other turn signal wires, and terminated them at a bolt on the inner fender. I did it to both front turn signals, and haven't had an issue since.

 

[Jonathan Hanson]

Seems to me Cromagnon solved this question authoritatively.

 

[togntime1]

So if it's a grounding issue, should I be looking to the grounds at the individual lights, or grounds somewhere else?

 

[Cromagnon]

Ground the individual lights with wires to a good source. There is no ground at either of the switches to be concerned with. Don't worry about grounding the instrument cluster.

 

[togntime1]

So I ran individual grounds from each light back to the neg battery post. Still same result. I can hear the flasher try to click and make them blink, but they only stay just stay on.

 

[Cromagnon]

Did you clean the sockets and bulb bases? Did you run grounds to the rear lights? What size wire did you use? It is still a ground issue, corrosion and loose connections exacerbate the problem. Show pictures of how you grounded the lights.

 

[togntime1]

Update. All lights, housings, and bulbs are new. on the front lights I have jumpers secured between nut and washers that run to neg post on battery. On rear I have jumpers connected to ground wires and ran them to neg post. I even tried moving one of the front lights and physically touched mounting post to neg post. No change.
I swapped the flasher with an aftermarket flasher and now individual turn signals blink, but extra fast. The hazards continue to work and blink at a normal rate. I searched some posts and found a similar thread, where some suggested that quick flashing could still indicate a ground issue. Since all of my lights on either side blink fast when their respective turn signal switch is activated, is there a common ground that I should start my search?

 

[EStein]

Man these are the worst kind of problems. Does the flasher itself ground to the firewall where it bolts in? I don’t know I’m just asking.

 

[Cromagnon]

Update. All lights, housings, and bulbs are new. on the front lights I have jumpers secured between nut and washers that run to neg post on battery. On rear I have jumpers connected to ground wires and ran them to neg post. I even tried moving one of the front lights and physically touched mounting post to neg post. No change.
I swapped the flasher with an aftermarket flasher and now individual turn signals blink, but extra fast. The hazards continue to work and blink at a normal rate. I searched some posts and found a similar thread, where some suggested that quick flashing could still indicate a ground issue. Since all of my lights on either side blink fast when their respective turn signal switch is activated, is there a common ground that I should start my search?

A picture of your grounding would help. The circuit is only grounded through the individual lights. Are you using LED or incandescent lights? Is the aftermarket flasher an electronic flasher? Are the correct lights wired to the right circuit, ie. the running lights are not on the flasher circuit? I'm not sure what the mounting post of the front light is. Read post #13 of this POST, it may shed some light.

 

[Cromagnon]

There is a write-up on here somewhere that has ground wires soldered or riveted to the light housings. There was another write-up where a replacement light housing was wired incorrectly crossing the running lights to the flasher circuit causing the same symptoms that you are having. The lights are different wattage thus drawing different currents.

 

[RWBeringer4x4]

Here is where I added the grounds on my lights (black and white wire) - not a great picture but it’s all I have. I believe it was 16 gauge. Drilled a hole, put a small screw through it, then added a star washer and nut over a ring terminal for a positive connection.

Then I routed the wire down through the turn signal stalk, and along the power wires into the engine bay where I terminated them at a fender bolt. This offers a much more positive ground than grounding through the base of the turn signal as originally designed.

 

[togntime1]

The aftermarket flasher is the green box kind with its own separate ground. I have my harness "roughed" in and I'm trying to test each circuit individually prior to me making the final connections. Lights are new OEM. I originally ran dedicated jumper secured by nut to the base of the light to the neg bat terminal. Then I moved the light and touched the base of the light to the neg terminal. I just rigged up a ground in the pic below. All same results. Work fine with hazards - steady solid with turn (no flash) both with original flasher - extra fast flash with aftermarket flasher. The brighter filament is the turn, the less bright filament is the running light. All let someone seem strong and correct in lamination.

 

[FJ40DDS]

I had the same problem with my ‘74 when I purchased it.

After trying everything else, as a last resort, I switched the two pigtails going to the front turn signal which solved my issue....