Accessory Fuse continues to blow

[ryan1522]

This is on '70 Cuda 440, no tilt, auto. Ok, I've torn apart my whole dash and steering column. Connections appear decent and I've forced powered the dash lights, wiper sprayer motor, road lamps....etc (all that appeared to not work before because the fuse kept blowing) I'm guessing it might be the actual switch having an issue because I can put the key in and the key buzzer stops but as soon as I rotate the fuse blows.

The car still starts and runs fine but I've lost power to many things. Any ideas? Is there a way to test the switch to see if it is bad? Thoughts?

 

[js29]

doesn't the key buzzer sound off when you leave the key in and open the door? when A fuse blows that means A dead short. if you put A test light in between the prongs were the fuse goes turn the key it will glow if there is A short. then start to unplug accessory's until the light goes out. that is were I would start. good luck, mark

 

[ryan1522]

Yes the buzzer does work. Nothing blows until I turn the key as soon as that happens the fuse blows. I can't test to see if the accessories on the fuse work unless I power them directly with a power probe because they only work with power and a good fuse, which never happens. Could a back ignition switch cause this? Could there be a short within the switch? the wires and connections all look good.

 

[js29]

So what u are saying is, u put power to the prong in the fuse panel and all is well? than your short has to be before it then. I suppose it's possible that your ignition switch is to blame. when I said to put A test light in the fuse panel I meant in series or hook it across were the fuse goes. u can use alligator clips one on each barb and hook the light up then turn on the ignition to power it up.

 

[ryan1522]

So what u are saying is, u put power to the prong in the fuse panel and all is well? than your short has to be before it then. I suppose it's possible that your ignition switch is to blame. when I said to put A test light in the fuse panel I meant in series or hook it across were the fuse goes. u can use alligator clips one on each barb and hook the light up then turn on the ignition to power it up.

Correct, I can manually power things. How would adding a light work? It would clearly turn the light on, and possibly burn it out, right? Power is getting pushed to the fuse once the key is turned, but too much and hence the fuse blows. I've got the dash lights, radio, wipers, ...etc all disconnected at the panels so I don't think it is any of those switches. All the wiring is wrapped in tape so doubt there is a short with-in the wrapped areas. Just haven't seen any clear evidence of bare wire other places.

 

[js29]

Im sorry I mean in place of the fuse, if the light glow's than something is grounded out. I was told this by an old time mechanic to save fuses to hook A light between the prongs in series so you don't blow 50 fuses while tracing A short

 

[ryan1522]

Im sorry I mean in place of the fuse, if the light glow's than something is grounded out. I was told this by an old time mechanic to save fuses to hook A light between the prongs in series so you don't blow 50 fuses while tracing A short

So I'll try the light in the fuse but I did go and get cheap aftermarket ignition switch today. At first it seemed like it would work. Didn't blow the accessory fuse but then it blew the fuse coming off the starter relay. It seems like the wires are a little different in the aftermarket. Anyone know which ways the wires are supposed to go? I just put the long black and red ones into the connector and plugged it in.

 

[AUSTA]

Remove the blown fuse connect an old headlight or similar across the fuse connection if you use to small a bulb the light will come on with the slightest current draw.
Once light is on try unplugging things such as radio , cigar lighter wire ,aircon plug on firewall , anything not engine related , large connector behind the L/H kick panel (The wires on my plug shorted to the pillar causing the fuse to blow)when the light goes off you have found the fault.

 

[js29]

that does make sense using A bigger lamp, as I think back the guy who showed me that only had A dome light bulb availible at the time.

 

[AUSTA]

See attached unplug both plugs from steering column use a beeper or test light should beep or turn on light when closed.
No wire should have a circuit to the frame or earth of the steering column

 

[js29]

What i find puzzling is his dash lights, I can't think of any place they intersect. and he said he unplugged all the accessories related to that circuit.

 

[ryan1522]

What i find puzzling is his dash lights, I can't think of any place they intersect. and he said he unplugged all the accessories related to that circuit.

Ok, so I noticed something. The orange wire for the dash lights is coming from the harness to the ignition connector, but there is no wire the seems too line up with it from the ignition switch. I have the 2 small for the key buzzer, and open space (which would line up with the orange), red, brown, purple, black, and yellow.

On the new switch I bought there appears to be a smaller extra black that lines up with it. Was the orange ever supposed to be put in there? From the wiring diagram it looks to be but why is there no wire coming from the ignition switch then? How is there supposed to be power getting fed?

 

[js29]

dash lights get fed through the head light switch, not key power.

 

[AUSTA]

The small black wire goes next to the 2 small reds on the column plug it is for key switch light if fitted No orange connects to the key switch
The small black is the key switch illumination light feed black on the steering column plug Orange on the dash side plug orange is fed from the dash illumination circuit