wiring prblems

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Jan 16, 2009 | 08:52 AM

12-02nimrod

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wiring prblems

I have a question about the wiring in the dash of my 65 ford f-100. Should the ammeter housing be postived charged with the key off? When the housing touches metal on the dash it sparks. Do i have a postive short somewhere? The metal on the instrument panel sparks also.
I have ordered a wiring diagram . I would like some input on what might be wrong.

Jan 16, 2009 | 01:09 PM

Roger Carter

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From: Corbett, Oregon

The terminals (studs) on the ammeter will be hot at all times, key on or off. If the housing is hot, at any time, there is a problem with the ammeter.

Said another way, "it is a fire waiting to start!"

I have seen the insulating washers around the ammeter studs deteriorate with age. These washers insulate the terminal studs from the ammeter body and housing. When the washers break down they allow the studs to come in contact with the housing/body.
Hope this helps.
Roger Carter

Jan 16, 2009 | 03:06 PM

daveengelson

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From: Boulder Creek, Ca

Not an authority, does not sound like the circuits fused, if not, strongly suggest you do. Swapped from std. instrument cluster to CC on my 65. Can only speak to how my alt. circuit works, I don't get a reading at the gauge with the key on or off, only when the engine is engaged and it usually starts charging and soon moves to the center. Installed a fuse between the alternator and the gauge. Happened to come across a metal fuse block and it seemed like it should serve the purpose. Posting pic of circuit another FTE member faxed me when I had a problem figuring out the circuit. Also posting pic of my fused box, it's difficult to tell, but there is a metal fuse block between those 2 connectors. It would seem to me any 50 plus amp fuse would work, perhaps able to pick 1 up at auto electric shop. With the connectors on the fuse block I used cupped insulators to ensure the connectors do not touch. Anyhow, may be of some help.

http://i300.photobucket.com/albums/n...WiringDiag.jpg

http://i300.photobucket.com/albums/n...s/IMG_0001.jpg

http://i300.photobucket.com/albums/n...s/IMG_0002.jpg

Jan 16, 2009 | 04:50 PM

camperspecial65

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From: seattle

They will only work/show movement when the key is anywhere but off ...if you turn it on accy and turn the turn signals on...you will see it move..when the engine is running at idle it will...or should read near center...slightly to the + side of the gauge(RH side) and when therpms hit a ceretain speed it kicks the alternator into 'overdrive'...so to speak...and the needle will move more to the right then previous...all assuming the gauge,wiring and alternator are all doing their respective jobs properly...
The is only 1 part in the entire truck with a circuit breaker...thats the light switch and its built into it. Theres also only one fusible link in the entire truck...this is the pink wire you see on the dash underside which goes into the rear of the ignition switch. This wire changes color as it switches plugs at the firewall main disconnect.
The ammeter is indeed always hot...so long as the battery is hooked up...

- cs65

Jan 16, 2009 | 05:12 PM

Roger Carter

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From: Corbett, Oregon

The original ammeter wiring for a '65-'66 is not fused, though fusing it is not a bad idea, as Dave suggested..
Also when properly wired (as original) the ammeter will show discharge movement, even with the key off. You shouldn't see a charge movement with the key off (engine not running) unless the ammeter is wired backwards. Turn on your headlights and see what happens.
Roger Carter

Jan 16, 2009 | 07:53 PM

daveengelson

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From: Boulder Creek, Ca

As noted, am not that knowledgeable about automotive electrical circuits, and can only relate how I ran the alt. gauge circuit in my 65. Originally held up on wiring the alt. gauge because of concerns with that many amps going to the dash or instrument cluster. Tried to stick to the diag. in the 65 F100-F750 wiring manual, with couple variations; athought have seen the circuit couple different ways. In the manual it show there is a 70 amp circuit breaker in series with the junction block and amp gauge. Can't recall if the metal fuse box I installed is a 50 or 70 amp breaker, but it has been working now for over a year with no problems. Just seem the way I ran the wiring addressed my concerns. The alt. gauge only reads when the engine is running, I do not get a reading across the gauge whether the ign. switch is off-on, or in the accessorry position. Anyhow, felt if the circuit should fry I would rather it do in the engine compartment and not fry the instruments, or dash wiring harness. Posting pic of circuit.

http://i300.photobucket.com/albums/n...WireDiagP8.jpg

Jan 16, 2009 | 10:15 PM

12-02nimrod

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Thanks guys for responding to the post. I think Roger has the right idea about the insulating washers being deterioated.I don't remember seeing any insulating on the washers.When we get some warm weather I will find out.

Thanks very much