Turn signal and brake light problems

Mikko_

Mikko_

Senior Member
On my '53 Customline the RH turn signals work both front and back, but flashes very rapidly.
On the LH the front lights up but doesn't flash and the rear don't work at all.

RH brake light works and LH doesn't.


All bulbs are ok and I have had the turn signal switch apart and cleaned it with no luck.

Could the flasher relay be faulty and cause these problems?
If so, how do I replace the 2 prong flasher that's in there now with a 3 prong?
(I have access to a 3 prong that I know for sure is working, hence my question)
 
Bulbs have ground since all other lights (tail, parking, low, high) works.

Is the turn signal switch itself supposed to be grounded to the steering column or does the switch have a separate ground wire?
 
feufeu said:
Hi Mikko,
I think bad ground for LH and perhaps flasher issue...
Click to expand...

Bad ground where? :o

The buld holder looks great, the tail light works and if I wiggle the bulb while the brake pedal is pushed down (or the signal on) still now sign of lighting up.

And the bulb itself works, lights up if I apply 6V directly to it.


Could it be possible the switch is bad internally and only feeds power to the left front turn signal (and the RH)?
 
typical schematic for flasher
 

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Had ground issues on my ‘50 Ford, ended up soldering a wire from the frame to the turn signal housing. All your grounds need to be clean/tight/bright, I ended up removing ground wires cleaning and reinstalling, it makes a big difference.
 
Thanks for everyones input.

Today I had the switch all apart and everything inside looks fine.
With the voltmeter I verified that I have 6 volts on both the X and L prong on the flasher.
The switch assembly itself is bare metal to bare metal on the column.
But I have 0 volts on the left rear turn signal bulb (but left rear parking light works fine).

So somewhere between the turn signal switch and left rear bulb there must be a break in the wire.
Looking at the junction block under the dash it looks kinda crusty so I think that will be my next target to check for bad connection.


I have 7 wires going into the turn signal:

LH front turn
LH rear turn
RH front turn
RH rear turn
6V in from the flasher
Brake light switch I think?
And what is the 7th?
 
Re the 7 wires: I found some images via google.
7th wire may be from P terminal on flasher to light up a lamp in the flasher unit. You don't say which type you have. You should be able to find a diagram for your unit online.

The rear flashers use the brake light filaments. The brakes also go through the unit so if the one rear flasher does not work, the brake light for that side should not work also as is the same thing.

Mart.
 
That's correct, no left brake light either.

I have a 2 prong flasher so no P terminal.


I believe that my turn signal indicators in the instrument cluster get their power from the wires that go to the front turn signals?
 
Like others have said, crzy light problems is usually a bad ground. Before you do anything, I would make up some wires to use as temporary grounds. Use these to ground the rear light housings to a good bare metal ground and see what happens. if it doesn't work then you can go further



To me this would be a first step because bad light grounds cause all types of odd problems.
 
I'm very pleased to say that everything is working now.

The wire between the left rear turn signal/brake light and junction block under the dash is broken somewhere so for the time being I just ran a new wire.

The inspection to get the Swedish title and plates is on monday afternoon so I was running out of time to make a permanent solution.
Long term plan is to replace the whole harness.

Thanks to everyone for their help.
 
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