Turn signal trouble shoot (1 Viewer)

[ollanik]

3 key questions;
Checked all grounds at light and they test good.
Turn signal clicks once and then stops on each side
Hazards work perfectly
Getting +- 8 volts at each light

1. Is 8Volts normal? If not, where could I be losing voltage?
2. Is there way to test turn signal on column?
3. Is this picture of turn signal module? If not, what is it?

 

[thebigredrocker]

That is the external regulator for your alternator.

 

[thebigredrocker]

Here's the flasher on my 71

 

[POTATO LAUNCHER]

On your 73 the flasher box is under the dash just to the left of the upper clutch pedal pivot.
Check the grounds inside the front turn signal housings. They should ground with tje mount bolt to the reflector. If you have a multimeter use the ohm setting to check continuity.

 

[thebigredrocker]

Coolerman once told me the two black white wires going to the Voltage regulator are most important grounds on my 71. They are the harness grounds. So you might scuff those up. I think the Ground runs through the VR(voltage regulator)bolts to the firewall, so you may want to pull it and scuff so it's well grounded to the firewall.

Not sure if the flasher unit needs a clean grounding surface to the firewall. Might not hurt to pull it and scuff the mating surface.

I've had instances of odd electrical behavior on both my 40's and it's always been a grounding issue.

As Potato launcher says, make sure the nut that fastens your front turn signals to the fender has a clean surface for the ground. Also at least one bolt that fastens the fender to the frame and front clip needs a good clean ground path. Same with rear signals, the bracket needs to be grounded to the frame.

Another thing to keep in mind is sometimes the socket that the flasher bulbs screw in to needs scuffed up to get really good grounds.

 

[ollanik]

Good advice all. The bulb socket one puzzles me as I have one of my dash bulbs that works fine out of the socket and attached to a ground but when I insert it in the cluster housing it somehow loses its ground.

 

[ollanik]

What about getting 8 volts at the lights - is that normal?

 

[crimsonaudio]

FWIW, when I replaced the taillights on my '72, I initially wired both the break and blinker wires backwards. After swapping them everything worked as planned.

I know the chances of getting both twilight wrong is only 25% in theory, but considering it was me working on them, I'd estimate the chances at closer to 100%...

 

[thebigredrocker]

I believe my battery charge is low, but here's what I get with my engine not running. Note: my flash is strong and the cadence is a consistent rythym

I get 9.7V at my front left GO wire when flashing & 9.7V to front right GY wire when flashing

Rear left GO is 9.5V when flashing and rear right GY is 9.5V flashing

Here's front left:

At the flasher unit I have the following

 

[thebigredrocker]

Might also clean the main harness to rear harness plug is you haven't done so.

Keep in mind I did my test, engine off with a low battery.

 

[thebigredrocker]

Good advice all. The bulb socket one puzzles me as I have one of my dash bulbs that works fine out of the socket and attached to a ground but when I insert it in the cluster housing it somehow loses its ground.

I was going to mention that next. Those "cluster housings" also require a clean ground to the dash. I believe I did that when my speedo gauge cluster was removed. So scuff up anywhere the dash indicators contact the dash. Carefully scuff the lead tip(+) of the bulb and the socket(-) the bulb twists into also(particularly where the two ground nubs on bulb lock into)

 

[Cleg]

"Turn signal clicks once and then stops on each side
Hazards work perfectly."

Here is an easy one to try.
Wires feeding the front Park/Turn lamps are Green/Yellow to Green/Yellow and Green to Green.
Unplug and swap the leads so the color codes don't match.

Mine was doing the same thing and this fixed it.
Either the wiring was swapped further back in the harness or the color codes on the park turn assemblies were wrong for the year... don't know... doesn't matter... it all works now.

 

[Coolerman]

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

 

[thebigredrocker]

Great explanation Coolerman.

I don't believe I've cleaned up my turn signal switch yet. Perhaps I'll clean it up, charge my battery and see if I can get my flashing voltage higher.

 

[CHCP]

Excellent info from Coolerman. I installed some after market rear combination tail lights on my 78 cruiser a while ago and found the vendor had put in low wattage bulbs causing the flasher not to cycle. But that wouldn't give you the low voltage that you currently have.

 

[ollanik]

I am making progress - left flashers work but not the right ones. Can I just run a ground wire to the front flashers to make sure they are grounded? Any other suggestions?

 

[ollanik]

Here's the flasher on my 71
View attachment 1465134

What is the silver colored unit next to the flashe?

 

[ollanik]

I am referencing the post from big red rocker In his picture above

 

[POTATO LAUNCHER]

Yes, remove the amber cover and ground the bulb socket some how to chassis ground. Maybe loop it with bare wire?

 

[thebigredrocker]

I think it's called a speed sensor. It had something to do with emmissions I think. I believe it somehow worked in conjunction with a Vacuum Switching Valve (VSV) that resided inside the drivers front fender. The VSV had all sorts of goofy vacuum tubes. I need to remove that speed sensor and install quick access bracket for a wheel gun