No power anywhere

Charging, starting, lighting, gauges, HVAC

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575Vaquero
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No power anywhere

Post by 575Vaquero »

I am now the owner of a 1972 f250. I can't get any power anywhere. Battery is hot, new starter solenoid. Battery connected to one side of solenoid, and one other wire on that side that goes to the horn relay. Small wire, red with a blue trace, I think, on the "I" terminal, brown wire on the "S" terminal and a wire on the other side going to the starter. It seems there should be another wire going to the switch from the battery side of the solenoid, but there's not. Is this correct, or is there something missing?

PO had a wire direct from the battery to the coil in an effort to get it started. It will crank that way, but no spark.

Any help will be much appreciated!
71Fe2O3
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Re: No power anywhere

Post by 71Fe2O3 »

There should be two wire lugs, in addition to the one containing the cable from the positive battery terminal, attached to that side of the solenoid. One of them has a wire that goes to the alternator. The other contains two wires, one of which splits off to to to the horn relay, while the main, larger wire goes on to the fuse panel, ignition switch, lights, etc.

Check out the main diagram linked below to see which wires you should have.
The second one shows the light circuits and also some of the wire color codes.
The third one is a comprehensive list of the wires and their color codes.

http://www.fordification.com/tech/wirin ... master.jpg
http://www.fordification.com/tech/wirin ... ghts01.jpg
http://www.fordification.com/tech/wirin ... -chart.gif
Fred

1970 F100 4WD short bed, 360 engine, very rusty plow and yard truck

1971 F100 2WD long bed, 302 engine, on the road

1968 F100 2WD long bed, 360 engine, stripping for parts
575Vaquero
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Re: No power anywhere

Post by 575Vaquero »

Thank you! I untaped the harness running from the right side upper firewall toward the front of the engine, but dont see any evidence of a broken or missing wire. I'll start at the point where the main power supply wire splits behind then gauge cluster and work back.

Another question:

On the harness coming from the VR, there are 2 wires coming from the "A" terminal at the VR. One goes to the noise supressor and the second one goes alongside a large black wire, I'm assuming a ground, to a small rubber cylinder. There is only one red wire coming out of the top of the rubber cylinder but it looks like a second wire beside the red one is broken off. Should there be a wire there and if so, where does it go? I can't attach a pic, I don't know how to resize it on my phone.
575Vaquero
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Re: No power anywhere

Post by 575Vaquero »

I talked to a guy at very helpful guy at Painless Wiring today. He said there is a fusible link that connects the battery side of my solenoid to tub harness that goes from the alternator to the VR to the 3 prong plug that plugs into the main wiring harness to the switch. Unfortunately he didn't make that sub harness and didn't have any tech information on it. My new question is, if I wanted to wire in a maxi fuse in place of that missing fulible link, what size wire and fuse would I need?
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sargentrs
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Re: No power anywhere

Post by sargentrs »

When I'm rewiring an old vehicle like our trucks I typically use a 30A fuse in the circuit from the battery to wherever I'm wiring in to.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
71Fe2O3
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Re: No power anywhere

Post by 71Fe2O3 »

As Sargentrs recommended, you can't go wrong with a 30 amp fuse. Also, 14 g wire should be fine for that application.

I checked out my trucks, and also the diagrams. I think I found the wires you referred to from the voltage regulator-one splits off and goes to a metal cylinder that you referred to as a noise suppressor, the other goes to the alternator. These wires are listed as 152 and 152A in the diagrams, alternator output to the voltage regulator. On one of my trucks, the wire to the metal cylinder under the voltage regulator dead-ends at a connector, and, interestingly, the truck runs fine-it starts, charges, and I run it regularly with no troubles.

The fusible link in the alternator-voltage regulator sub-harness shows up in the diagram, the black dot on wire 38A and 152, and you could likely build one or find a used one. I may have one on my parts truck if you are interested, and, if mine is no good, it is likely that somebody here has one.

Do you have wires between the alternator and the voltage regulator? I have seen alternator harnesses for sale-I don't remember the details, but I think Carpenter and the other popular vendors carry them-they contain the connectors to plug in to the back of the alternator, and may have the fusible link and all the correct wires-one of these might save you some time and trouble-all new wires and connectors might give you peace of mind compared to homemade or used units.
Fred

1970 F100 4WD short bed, 360 engine, very rusty plow and yard truck

1971 F100 2WD long bed, 302 engine, on the road

1968 F100 2WD long bed, 360 engine, stripping for parts
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