View Full Version : Electrical: Blowing 14 Amp Fuse on 1951 Turn Signal Setup

07-11-2017, 12:49 AM
Installed all new wiring, provided by Lark Works, on my 1951 Land Cruiser. Seems everything checked out, until I went to check if the turn signals worked. Here is the rundown of what happened in chronological order:

- Both rear turn signals worked, no pilot lamps (arrows) in the the speedometer housing, no "tick" noise from the flasher, and no front turn signals from the parking lamps.

- Removed front headlight housings to see if bulbs were burned out, verified they were not and place back in.

- 2nd attempt: Drivers side rear turn signal worked, no rear passenger side this time, speedo housing pilot lights and front turn signal lights are still not working, tick noise from flasher, also not working.

- 3rd attempt, nothing working, checked inline 14 amp fuse on wire from ignition to flasher relay. Fuse is blown, replaced fuse.

- 4th attempt Both rear turn signals worked, no pilot lamps (arrows) in the the speedometer housing, no "tick" noise from the flasher, and no front turn signals from the parking lamps.

- Replaced flasher with new 6 volt heavy duty flasher. Blew fuse before being able to engage turn signal lever.

- Replace new flasher with original flasher. Still blows fuse before being able to engage turn signal lever.

I went and verified all connections, looked for any open circuits. One thing I find interesting is that only the drivers side parking lamp turns on when headlight switch is engaged. Aside from that, I get brake lights, taillights, headlights, hi-beams, dash lights, map light, dome light, horn, even the clock works!

07-11-2017, 11:02 AM
hard ti tell what is going on from your description as it seems the trouble is changing as you test the system. I don't know where you have a 2 or 3iwire flasher; I believe they work differently. I do not have a 1951 wiring diagram.
I don't believe that the parking light should illuminate when the head lights are on. The indicator on the dash should illuminate when the turn signal flashes. I don't know if it should illuminate when the signal light illuminates or when it turns off. Yes the flasher should click as the turn signals blink.
First you must locate the source of the short before you can solve why the dash indicators do not illuminate.
There must be a short someplace to blow a 14 amp fuse. Rather then keep blowing a fuse; I wold replace the fuse with a 6 volt test bulb (the same size as the directional signal bulb) in series where the fuse was. If there is a short the bulb will illuminate. The more solid the short the brighter the bulb will illuminate. Another reason to use a test light rather then a fuse is; you do not want the short to clear itself. Yes you can also use a volt meter set to volts in series with the fuse location rather the a bulb.
Assuming the test bulb is illuminated; With the directional signal in the off position. I would remove all the bulbs one at a time until the test bulb went out. If it stays illuminated I would next start undoing wiring until the bulb goes out.

07-11-2017, 11:32 AM
Obviously, there is a wiring conflict resulting in a "short to ground." Blowing the fuse could very well be saving you from burning the car to the ground. Depending on your electrical skills, you could replace the fuse with the same rating circuit breaker. That would mean removing the fuse, wiring up a temporary "in-line" circuit breaker jumper to connect until you are able to trace the circuit, and correct the short. That way, you would not have to keep replacing fuses because the circuit breaker would "reset" once it cooled down.

Trying to understand exactly what you have written...exactly what fuse (where) in the wiring harness? I have a '51 Land Cruiser, and replaced the entire harness with one I built myself. It has been a long time since I did it, and am having trouble recalling just where everything is on that particular car. Some of these cars have a main power circuit breaker near the amp meter going to the ignition switch. Some headlight switches have either a fuse or a circuit breaker. Either way, you need to isolate which circuits are downstream (power fed) from that fuse, and check each connection from there. Last year I had a short on my '55 Truck. Turns out it was a tail light wire that had gotten pinched along the frame. After a long time of rubbing, it finally abraded the insulation enough to short against the frame rail. (My bad:o) Once I found the short, I re-routed the wire and all is well. Hope it turns out well for you too.:)

07-11-2017, 04:48 PM
If it is possible to install a 2 Prong Flasher in the 3 Prong holder THAT would screw things up. :(

I think the issue is in the Flasher or it's Holder, since the "Short" happens BEFORE you turn on the Turn Signals!

I assume you had the Key in "ACC" mode, or maybe "IGN ON" Run mode, (not a great idea for the points).

07-11-2017, 06:15 PM
I don't know if this is large enough to help.