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Burning Fuses & my patience..running out of both

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I keep burning the fuse in my fuse box that feeds the green wires (brake lights, fuel gauge, temp gauge and heater fan.)
Amongst other things. Obviously (I guess) I have a short somewhere and it is driving me nuts. I get just a few minutes out of a fuse. I also have the relay for my electric fan wired into this circuit. What is the best way to trace down where I might have a short? Or what else would make a fuse overload? Could it be that I have too much on this one circuit? The fan's main source of electric current is directly off the battery and the relay only uses the green wire circuit to activate. I am running out of fuses...and patience.

Bill
 
Bill,

Why don't you start taking things off that circuit one at a time until you DON'T blow the fuse? That may help you find the problem connection.
 
Re: Burning Fuses & my patience..running out of bo

Hi Bill,
I had my 14" fan in this same circuit. I had the same trouble as you are having. I put the fan on it's own circuit using an inline fuse holder to see if it helped. That took care of the problem.
Now I just have to decide on a permanent solution for placing the fuse.
Roman
 
Re: Burning Fuses & my patience..running out of bo

All suggestions make sense guys. Seems the problems started when I #1-put in cooling fan, #2-rebuilt heater, and #3-added third brake light. The brake light is an LED bar and draws minimal amps and is tied inline into brake lights wire. The heater fan I had to jump off the hot wire to the overdrive solenoid because I seem to have lost the hot lead for the fan. Could this be a problem, running both a heater fan and an overdrive solenoid off the same little wire? I thought of running a separate circuit for the heater fan to the unused block in the stock fuse box. The cooling fan came with it's own wiring harness and relay that cannot be wired wrong. Well, I can wire anything wrong but this one had little words on the wires. I am not sure that some of the words weren't idiot and jerk. Whatever. I really hate tracing shorts. Will just have to work it out. Merry Christmas.

Bill
 
Re: Burning Fuses & my patience..running out of bo

My brother and I were rewiring his Vixen and decided to install an electric fan. I thought that it would be neat if we used the disused fan switch (from the removed heater) on the dash to wire up a "parade" override feature. In the off position the fan would cycle automatically & when the situation called for it, you could operate the fan manually. We both thought it was a good idea and I got to work with the installation. Later when I had sorted the wiring, I presented him with my proposal making use of an extra relay that had been on an E-type. Feeling rather proud of my nifty setup, I was pointing and walking around the car when I became aware that he had strangely become silent. He was apparently distracted by something I had in my hand. The Lucas relay...
 
Re: Burning Fuses & my patience..running out of bo

Bill -- if a fuse repeatly blows you can rig up a simple test light -- remove the fuse and connect the bulb in its place. I keep a test light handy anyway (2 leads soldered to a tail lamp bulb w/ alligator clips at the ends).

When the fuse would ordinarily blow, the bulb will light (and create a load protecting the circuit). Sort of a visible re-usable fuse. Some even wire a 12V buzzer this way to make tracing the short that much easier (when the light goes out or buzzing stops you have disconnected the offending component).
 
Re: Burning Fuses & my patience..running out of bo

Excellent suggestion, George. I have an old GM headlight warning buzzer wired up this way. It's easier to use than the light, when you are head down under the dash.
Bill, I think I would start with the heater fan motor circuit. Didn't you have a problem with that before?
Jeff
 
Re: Burning Fuses & my patience..running out of bo

Great ideas, guys! I am off this week and will pursue this with a vengeance.
Geo, my total lack of knowledge of electricity makes me ask the question: No fuse, no flow of electricity. 12V bulb in it's place would allow the juice to flow through the bulb elements and light the bulb. Where would the failure show up? Again, you are explaining to a complete neophyte.

Bill
 
Re: Burning Fuses & my patience..running out of bo

Bill, as I'm sure you are aware, just be patient, and above all, methodical.
Good luck, and Merry Christmas.
Jeff
 
Re: Burning Fuses & my patience..running out of bo

[ QUOTE ]
...the question: No fuse, no flow of electricity. 12V bulb in it's place would allow the juice to flow through the bulb elements and light the bulb. Where would the failure show up?...

[/ QUOTE ]

I'm no EE (shoot I have to imagine that electicity is like water running thru little pipes to visualize these things) but the idea is that the bulb only lights when it finds a ground. With all components on the circuit switched off it *should* find no ground (light off). Switch something on and it will glow as the component (dash light, heater motor, etc) provides a current path with the buld in series with the component.

If you have a short the bulb will glow even with everything switched off. It will only go out when you disconnect a wire between the fuse block and the short.
 
Re: Burning Fuses & my patience..running out of bo

Geo comes through with another amazing piece of knowledge tip/trick that will now make all of our lives much easier.

Basil -- add another gold star to Geo's name on the class roster /ubbthreads/images/graemlins/wink.gif

Actually, Geo, this one should definitely go into the knowledge base.
 
Re: Burning Fuses & my patience..running out of bo

I am planning to hook my 14" electric fan straight to the battery. The control unit I bought for it has its own 25amp fuse. This way I won't overtax the underfused electrical system of the TR6. Just my 2 cents worth.
 
Re: Burning Fuses & my patience..running out of bo

My fan is connected directly to the battery, totally independant of the wiring harness except for the small tickle wire to the relay. I just have to start unplugging everything one wire at a time to find the offending circuit. Not fun to lay on your back to access the wires under the dash. Gotta get up my nerve to tackle it.

Bill
 
Re: Burning Fuses & my patience..running out of bo

I know what you mean Bill. Been there done that and my 53 yr old body ached for a day or 2. lol
 
Re: Burning Fuses & my patience..running out of bo

Getting under the dash can be kinda like doing a distal buccal fill on #16, eh Bill? Okay, my mechanical expertise is limited so my suggestions are always the most remedial, but I had a problem with the the heater switch itself grounding out on the dash support mount where it fits. My switch didn't seem to fit too well and strangely there are some exposed hot terminals on the switch which made contact whenever i pulled the switch on. I "resolved" it by simply covering the unused terminals with electrical tape. Still looking for a better solution, but at least the shorting has gone.
 
Re: Burning Fuses & my patience..running out of bo

Bill
Try it from the other end and disconnect the circuits one by one until you find the bandi; IF, it is easer to get to.
 
TR6 Bill, Yes you have too much load on that one circuit. I think if you relocate high current circuits to other locations you can solve this problem. The heater fan should be given its own circuit and in line fuse direct from the battery. I do not know what "Amongst other things " might be. Your description of the fuse failure is typical of circuit over loading. I would suggest using a larger fuse but that may cause unacceptable wire heating which would be worse.---Fwiw--Keoke
 
Well, I finally isolated the source of my blow fuses. It is indeed the new heater motor. I ran a totally independent circuit for the heater. No matter what combination of wiring I do, I keep blowing a fuse. I even isolated the motor away from the switch and blew fuses. Either I have a short inside the heater housing (Man I hope not) or a bad motor (Man I hope not). Either way, a few more tests to see if I have a true short then, well, you all know the rest of the story. Wanna buy a TR6 anyone? (I bet it will run with no fuse. I wonder If I could get away with a larger fuse.)

Bill
 
Bill, if you have an internal short in the motor, all a bigger fuse will do is delay the time it takes to let the smoke out. Best (as always) to complete the troubleshooting, and do it right. Of course, you know that. You're just in denial! /ubbthreads/images/graemlins/grin.gif
You wouldn't want to set the thing on fire, would you?
Maybe I shouldn't have asked that. /ubbthreads/images/graemlins/eek.gif
Jeff
 
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