Turn Signal Conundrum

macdonge

macdonge

Senior Member
Finished wiring up a new turn signal switch (VSM 900 from one of the major reputable suppliers) for my '30 Roadster recently - but only after some effort to find a short circuit that would cause the fuse to blow whenever power was supplied to the circuit. It turned out to be a short inside the switch itself (see pics). The blue wire supplies a common load bus with 6V (first picture). I found that the black ground wire was shorted to this bus (second picture). A bit of tape and bicycle tube fixed it (third pic)!

With the exception of a dim pilot light, all was fine thereafter in terms of its operation. Then I decided to change out the cheap thermal BV535 6V flasher that had been supplied with a Novita LL535 electro-mechanical flasher. Well, the flash rate improved a bit & the pilot light brightness improved substantially (and it was nice to hear the relay clicking - something the thermal flasher doesn't do) but when the lights are turned on (in either parking, headlights or bright position) the flasher (signals) doesn't kick in.

Thoughts anyone?
 

Attachments

  • Frelighsburg-20180411-00701.jpg
    Frelighsburg-20180411-00701.jpg
    59.1 KB · Views: 134
  • Frelighsburg-20180411-00709.jpg
    Frelighsburg-20180411-00709.jpg
    48.3 KB · Views: 125
  • Frelighsburg-20180411-00711.jpg
    Frelighsburg-20180411-00711.jpg
    45.1 KB · Views: 114
Does your setup use the original brake lights and parking lights or did you add separate light assemblies front and rear?
 
Six years ago I installed the LOGO LIGHT turn signal kit on my Model A and it has functioned flawlessly from day one. The kit is expensive but in my opinion well worth it.
The signal controller emits a sound similar to a cricket chirp.
 
Last edited:
Check voltage at flasher x terminal. I had the same problem with my BV535 until I moved the feed from the brake switch connection up to the junction box on the firewall. Could be the new flasher needs a bit more V. Start the car and adjust the generator third brush with lights on and see if that helps.
 
Are the cowl lights acting only as turn signals or are they also wired into the lighting harness?
 
Badpuppy - thx for the suggestions. I'm away from home for 4 or 5 days but will give them a try once back.

Flathead - the cowl lights are wired with a switch so I can use them as intended as well as for signals.
 
My cowl lights have dual filament bulbs. I use the brighter of the filaments for my turn signals. Signalstat 900 system from Sacramento Vintage Ford, working perfectly for 7 years.
 
macdonge said:
Flathead - the cowl lights are wired with a switch so I can use them as intended as well as for signals.
Click to expand...

That's a smart way to avoid the cowl conversion, which I don't like. You can eliminate the switch with two 2-amp diodes (1N4002), striped end to the lighting switch and other to each bulb. Just remember to turn off parking lamps before you pull away from the curb, flasher won't work.

I thought I'd be a smartypants and fitted two 6V relays and resistors so cowl lamps glow dim and flash full bright when signaling. Works, but in retrospect it's kind of a dumb idea - who signals when they're parked?? And it's a royal snarl behind the kick panel. But it's done, so I'll live with it.
 
Oops :o - yeah, 1N400x diodes are all 1A, last digit is voltage rating. Been a while, and I should know better than trust my memory at my age. There are plenty of diodes available for cheap, just use ones rated 2A or better.
 
Badpuppy said:
Oops :o - yeah, 1N400x diodes are all 1A, last digit is voltage rating. Been a while, and I should know better than trust my memory at my age. There are plenty of diodes available for cheap, just use ones rated 2A or better.
Click to expand...

Badpuppy, I wasn't trying to point out your mistake, I am just looking for a diode to prevent feedback to my indicator light when my engine is running. My indicator glows slightly when the switch is in the neutral position. Not a big problem, just annoying (to me). :p:p
 
Y-Blockhead said:
Badpuppy, I wasn't trying to point out your mistake, I am just looking for a diode to prevent feedback to my indicator light when my engine is running. My indicator glows slightly when the switch is in the neutral position. Not a big problem, just annoying (to me). :p:p
Click to expand...

Well, mistakes need to be pointed out, glad you did.

There isn't any kind of feedback to the pilot indicator, it's a separate parallel circuit inside the flasher, flashes opposite the signaling bulbs. Flasher is activated with positive voltage at L terminal, so there shouldn't be any current flow through the flasher in center position Most suspect is the flasher itself, something conductive between X and P terms. Try cleaning base and socket with alcohol swab.

Of course, this assumes a standard 3-pin thermal flasher.

One other thought - if you wired tail lights as turn signals, you could have a pinched wire inside the t.s. switch. Tails are on with any other lights, so the tail switch wire is hot.
 
Last edited:
Well I think the booby prize goes to Badpuppy on this one. When I first tested the electro-mechanical flasher, the battery wasn't fully charged. I charged it and the flasher worked fine with the lights on - but for just one cycle (left/right/engine off). Seems my battery isn't holding a charge for long - something I've suspected for a while since it seems to take an inordinate length of time to charge fully. Needs replacement I guess!

Note that when the engine is running the flasher also works fine with the lights on. Just added confirmation of Badpuppys theory. Thanks all for the input! (I'm using an alternator, by the way, so can't "adjust the third brush")
 
Yeah, alternator is the way to go (me too). Bring it out of the iron age, unless you're a diehard purist. Just adding 50CP headlights stresses the old genny pretty bad.
 
You must log in or register to reply here.
Back
Top