poppin' fuses

[JSeery]

Originally Posted by Mike in AZ

looking at pic of gauge cluster with two gauges....diagram shows 4 wires, i can only see 3??....maybe the gauges need to be installed in dash??.....6V positive ground system??..maybe you have a short in the ignition switch??.....Mike

How would a short in the ignition switch blow a fuse? There is no fuse in the ignition circuit!!!

[ford38v8]

Originally Posted by JSeery

.... The terminal on the fuse block is used for the major connection point for all of the hot wiring from the battery, is this the source of the confusion? Just because the main hot connection point is a terminal on the fuse block does not mean it is fused!....

Originally Posted by WQ59B

....The 'ON-OFF' switch is labeled 'ignition switch' on the schematic. That switch has a 'batt' terminal the schematic shows connected to the 'fuse block'.....

The ignition is fed from the fuse block, not from the fuse on the fuse block.

[JSeery]

This is how it needs to be wired up. The ignition switch should not have any path to the fuses and turning the ignition switch on and off should not be able to blow a fuse.

Make sure the wire from the battery to the BAT terminal on the ignition switch is not connected to a fuse (use a direct wire from the BAT side of the starter SW to the BAT terminal on the IGN SW. This is not the same as the wiring diagram, but gets it completely away from the fuses so there can not be any connection between it and the fuse itself. The wire from the Starter SW to the IGN SW is HOT all the time.

Make sure the ONLY wire going to the gauges is from the IGN SW Gauge Terminal. This wire should run from the IGN SW Gauge Terminal to the Temperature Gauge (the terminal with the strip connecting it to the Fuel Gauge. This same terminal should have a wire to the Oil Press Gauge. The other terminal on each gauge should go to a sender. The Fuel gauge to the fuel tank sender, the Temp gauge to the temp senders and the Oil Press gauge to the oil pressure sender. There should not be any other wires connected to the gauges. The wire to the gauges is only HOT in the ON position of the IGN SW.

The IGN SW IGN terminal connects to one side of the resistor and the other side of the resistor connects directly to the coil. There should not be any other wires connected to the IGN terminal of the IGN SW or the resistor. The wire to the resistor is only HOT in the ON position of the IGN SW.

The Fuse part of the Fuse Block should have a strap connecting one end of the two fuses together. This is where the Hot wire from the Battery (from the BAT side of the Starter SW) and the HOT wire from the Voltage Regulator BAT terminal connect. The ONLY thing that connects to the other side of the fuses is two wires to the Lighting SW and one wire to the Brake Light SW. No other wires should be connected to the Fuses. The Fuses are for the lights ONLY and nothing else. The only thing that can blow a fuse is something in the lights because that should be the only thing connected to the fuses. The wires to the Light SW and the Brake Light SW are HOT all the time.

Unless there are additional wires connected or shorted across or misconnected there is not any way that the IGN SW can be the source of a fuse blowing problem. There should be no path for current between the IGN SW and the fuses.

[JSeery]

Originally Posted by ford38v8

The ignition is fed from the fuse block, not from the fuse on the fuse block.

That is correct (and the original Ford wiring), but to solve this problem once and for all I am suggesting that he remove any wire between the fuse block and the ignition SW and wire the ignition SW BAT terminal directly to the BAT side of the starter SW. Then there should be no way it could be confused or mixed up.

[JSeery]

[QUOTE=WQ59B;1262156]
The 'ON-OFF' switch is labeled 'ignition switch' on the schematic. That switch has a 'batt' terminal the schematic shows connected to the 'fuse block'. Where you lose me is the difference between circuit breaker & fuse; is the wiring routing OK but the fuses need to be replaced with circuit breakers?

The Ignition SW is NOT connected to the fuses/circuit breakers, period. This is most likely your problem. It was originally (original Ford wiring) connected to a terminal ON the fuse panel. This was just done for convenience and has nothing to do with the fuses/circuit breakers. As I suggested above to get rid of this confusion just get the wire off of the fuse block, then it can't get mixed up with a fuse.

[Terry,OH]

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I have a Ford schematic diagram that may make the lighting and ignition circuits a bit easier to view and understand. One fuse for the headlights & hi/low indicator and the second fuse for all the rest of the lighting. The ignition, horn, gauges, starter system, charging system & cigar lighter (if you have one) are all without a fuse. Send me a PM with your email address, I will email it to you.

[WQ59BJR]

Hi all. I'm working with WQ59B on the COE and just joined your awesome forum. You guys/gals have been a tremendous help. Can someone (JSEERY?) please clarify something for me? The dash mounted light switch has 4 terminals on it. I have no idea if it's the original one. Currently, terminal A is connected to a fuse (Fuse "A"). Terminal B would be connected to the front parking lights but they were beyond repair and have been removed so this terminal is unused. Terminal C is connected to the tail lights and lights on the gauge cluster. Terminal D is connected to the headlights hi/low beam switch. All the lights appear to be functioning properly. Here's my question: If I need to connect another wire to the 2nd fuse (Fuse "B") from the light switch, which terminal on the light switch do I put it on?

[flatheadmurre]

To have 2 fused circuits the switch has to have 5 terminals, 2 separate inputs and parking, rearlight and mainlight out.
So if its 4 terminal you can only have 1 fuse for all of the lights.

[FrankWest]

wow! Sorry to be direct...But.. Buy new harnesses from Rhode Island wire and remove everything you have and wire it properly. No fuses in the ignition!! Only for the lights!
It is hard enough when you do things the right way, but when you have a cludge...
It is almost impossible to get it working properly.
Starting with the right stuff and diagrams they send with their harnesses make the job fall into place... Wire harnesses are a major part of any car....Get the right stuff..I hate to see you torture yourself..
http://www.riwire.com/
It is worth every penny....Please buy proper harnesses made for your car.

[Terry,OH]

Sounds like the original 40 head light switch with four terminals and wired as you describe. This switch will not accept two hot wires from two fuses and have part of the light load on one fuse and part on the second. The 41 head light switch has six terminals, and will accept hot wires from the two fuses. It is the switch internals, as well as the number of wire terminals that make the two switches so different. 40 does not use two fuses to feed the lighting circuits. If you want to get the truck wired, you can abandon one of the fuses. Run One #12 or 10 AWG wire from the one fuse to the light switch. You can leave the parking light wire off do not connect anything to this terminal. The tail lights, dash light dimmer rheostat, and the license plate light are all on the terminal across the switch from the Hot fuse wire. The terminal at the knob side of the switch is the #12 AWG wire to the common of the foot operated dimmer switch. Put one 20A fuse in the light circuit.

[JSeery]

This IS NOT the correct lighting switch diagram for your application (it is for later years), but it might give you an idea of how they are wired. There should be letter by the connectors to indicate what they are for.

B is a Battery connection
H is Headlight connection
P is Parking lights connection
R is Running lights (Tail Lights)

I don't know if all of the Light SWs are labeled, but a lot of them are.

[WQ59B]

OK, I believe it's nailed down now.
Moved the ignition feed off the fuses. Changed the arrangement a bit of the wires going to the fuses.
Also did take apart the oil pressure gauge, snipped out the thin metal pieces between the twin holes on the back and carefully aligned/retightened it down. Tested the gauge itself, the gauge in the cluster and the gauge in the dash. Zero continuity. I theorize that I got this gauge, nearly NOS, because someone took it out of a car early in it's life and it sat on a shelf for 70-some years.

Ran incremental hot tests: ignition alone, then plus coil wire attached, then plus gauges wire attached. All lights work, zero fuses blown.

HUGE thanks to the knowledgable advice here, and the dogged tenacity of WQ59BJr! On to the next arena: the distributor.

[JSeery]

Sounds like great progress!

[duanedunlap46]

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