Turn signal flasher doesn't indicate bulb-out

[Kartner]

I'm currently trying to setup a lighting and signalling system on a vehicle with no system at all currently present. I've got it almost entirely operating how I would like it to with one exception... when a turn signal bulb is out, the frequency of the flashing does not change as it commonly would in a car.

It is a 12v system with headlights, brakelights, turn signals, hazards, etc. The flasher unit I'm using is a 3-pin unit with terminals labelled 'X', 'P', and 'L' capable of supporting 10 bulbs. It is usually flashing only 2 bulbs, and at most 4 for the hazard lights.

The way I currently have it setup is to have power applied to the terminal marked 'X', and the load (lights) connected to the terminal marked 'L' and then grounded through the lights. I also have the dash indicator light connected to 'L' even though it should be connected to 'P', but I don't think that's the issue. It works, the lights flash when the switch is activated. But when I remove a bulb to simulate a burnt out bulb, the system just keeps on flashing at the same rate, I want it to flash faster so that the driver knows a bulb is out.

I think I might need a different kind of flasher unit, but anywhere I have asked they hand me one that performs the exact same way while telling me it will do what I want it to. Am I hooking the flasher up to the circuit wrong? Do I need a different flasher unit?

Any help is greatly appreciated.


Kartner

 

[jons999]

Normally when a bulb is out the flasher cycles faster because of the increased current flow through the bimetal strip in the flasher unit. If your flasher is capable of supporting ten bulbs maybe the increased current flow isnt enough to heat that strip up faster? Thats the best i can come up with at this time of night without frying my brain

-Jon

 

[drlguy]

You need a junkyard flasher out of a vehicle after 1993. These are electronic and have a input (X), an output (L), and a ground, but they are not labeled the same as an aftermarket heavy duty variable load (trailer) flasher.

The car you get this from (I suggest a Toyota or import) should have the same total bulbs as your car. Two turn signal bulbs in the front, 2 in the back is most common. This flasher will change rate of flash from normal 'feeding' 2 right side bulbs (or L), and then will change modes to bulb out 'fast flash' if one right side bulb is disconnected, while one continues to function (like a real world burn out situation).

This bulb-out function is in the federal code for US cars since 1970, but only factory flashers have this capability. Around 1993 they upgraded the US standard for flashers, and they went from thermal to electronic (hence the need for a third prong - ground).

Pop the case off of the junkyard flasher like an automotive relay. The base terminals that have continuity with the relay type contacts inside the flasher are probably the X and L - no continuity is probably ground. Current should flow through X to L when the flasher is at rest and waiting to be connected. Maybe get 2 in case you burn up the first one.

Cars with quad bulbs on one end need a six bulb car flasher (3 bulbs per side) from the junkyard. They alert when any one of three bulbs might fail.

Hope this helps.

Here's a link to how the turn signal system works:

http://www.daytime-running-lights.com/blank?pageid=2&catstart=0&prodstart=0