The Stovebolt Site Forums The Shop Area The Electrical Bay Turn signal fuse keeps blowing

I installed a 6v turn signal kit without the hazards a few years ago. No problems until recently when I started driving at dusk and have the head lights on. Once the lights are on, I get one use of the signal and that's it. There is an inline buss fuse between the ignition and relay that is 6amps. The other lights are not affected by this. It may also have popped when I turned the heater fan on. They share the same terminal on the ignition. Maybe someone can explain this scenario to me.

Should I use a larger fuse? Can I change the glass fuse for a modern blade type?

have to see the exact layout/connections to say what's going on, but if it's all hooked up separate than running other things should have no effect at all .... I'd be inclined to use a 9 or 10a fuse for signals and you can use any type fuse you want, but that won't make it better

Bill

I am assuming that the 6A inline is the one blowing. Anyway in general you calculate all of the amp draw on a fuse and size to that number or near. Add up all the watts of the bulbs (available on the internet, using the bulb number) and motors, etc. and divide by 6(V), that will give you the total amps drawn on items that could be energized at the same time thru that fuse. Probably should check the wire size while you have the numbers handy. Technically, fuses should be sized to wire size. They are really for fire protection but we assume they are to protect devices, which they do. But it's all related anyway.

bartamos, going by your suggestion I came up with the following. The signal only operates two bulbs at a time. I checked the bulbs and they are rated at 21watts each. So 42/6=7amps, I guess that might explain why they are blowing the 6amp fuse. I'm surprised why this only occurs when the headlights are on even though they are on a different circuit. Coincidental I suppose. Will try a 10amp fuse and see what happens.

If this did not happen before.
I would assume there is a short to ground.
You could have a faulty Turn Signal Relay that is shorting to ground.
Replacing with higher amp fuse is not suggested until
a fault is NOT found.
Blinks once then blows with headlights on, tells me signal wire may be crossed with headlight wire.

So the signals don't go thru the relay but the headlamps do, right? Also I was thinking that the relay coil draws amps too. But as has been said, to all of a sudden start blowing the fuse, it may be a short or some component failing like the relay itself, a bulb or the flasher. Check all wiring involved before upping the fuse. I agree with jorb. The turn signal bulbs are only on for 1 blink at a time, so the draw against the fuse is not constant. Leans towards something else wrong. Put 4 new bulbs and a new flasher unit in with same 6A fuse and see. If no improvement, Draw yourself a schematic of how the headlights, relay, signal bulbs, fuses, headlight switch, stop switch and heater are wired and study it.