Alternator indicator lamp

Charging, starting, lighting, gauges, HVAC

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Bubi
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Posts: 35
Joined: Thu Jan 02, 2020 3:01 pm
Location: Germany

Alternator indicator lamp

Post by Bubi »

Hi,

my f250 have a instrument cluster with amp- and oilpress-gauges.
From my other cars I be used to have lighting lamps when the ignition is on. :)

Now there is a old (parking-brake)indicator light in the cluster bezel, which has no function yet. I now want to use this as an alternator indicator light.
I plan to connect the lamp one side on the green-red Wire 904A and the other side on 297 Splice/S7, analogous the wiring without ammeter.
But the ground connection over the oil-press warning lamp -> oil pressure switch makes me a little insecure. This connection is only active when the engine is not running and the oil-pressure switch connect with ground. :?
When the engine runs, the ground connection is disconnected.
The alternator indicator lamp shines, when the voltage difference between 297 splice/S7 and 904A is 12V or smaller. When the engine is running and the voltage difference between this points disappears, the lamp goes out.

I hope anyone can have a quick look over my consideration. I don´t want to kill the alternator regulator in smoke... :D

Thanks and regards...
72' F250 360, LWB, SportCustom, 4 on the floor.
1994 BMW 540i touring manual six speed.
2008 Ford S-Max 2,5T - powered by Volvo :-)
Bubi
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Posts: 35
Joined: Thu Jan 02, 2020 3:01 pm
Location: Germany

Re: Alternator indicator lamp

Post by Bubi »

I made a thinking error...

The voltage comes from 297 Splice/S7 then over the lamp to 904A.
So there is no problem with the ground over the oil pressure Switch.

Regards...
72' F250 360, LWB, SportCustom, 4 on the floor.
1994 BMW 540i touring manual six speed.
2008 Ford S-Max 2,5T - powered by Volvo :-)
390FE1972
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Location: Colorado Springs, CO

Re: Alternator indicator lamp

Post by 390FE1972 »

Hello Bubi, I see from the welcome mat that you have a 1972 with a 360 FE engine. You mention that your F250 has a instrument cluster with amp and oil pressure gauges. Is the instrument cluster you have in your truck an original cluster? The reason I ask is that the instrument cluster's with gauges vs. the "idiot" lights have two different wiring harnesses. You mentioned "there is a old (parking brake) indicator light in the cluster bezel which has no function yet". Your not talking about the headlight high beam indicator light are you? Let us have some additional info on this. If you click on this http://www.fordification.com/library/in ... tegory/230 then click on the Album 1969 Ford Truck Memorabilia you can find the 1969 Ford Trucks Operator's Manual, on page 03 there is a drawing of an instrument cluster that shows the "idiot" Oil and Alt lights. The "Delux panel has an Ammeter gauge and an Oil gauge.

Regards :thup:
1972 F250 Sports Custom 390 FE C6 2WD Dana 60 4:10 gears
Bubi
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Posts: 35
Joined: Thu Jan 02, 2020 3:01 pm
Location: Germany

Re: Alternator indicator lamp

Post by Bubi »

Hello,

the Instrument Cluster with ammeter and oil gauge is original.
The high beam indicator lamp is in the middle of the speedo.
But one of the POs drilled a hole in the instrument bezel to install a parking brake indicator lamp.

So I think, I can use this (actually senseless)lamp for a alternator indicator lamp.
The wire 904A, green/red is connected on the port at the alternator regulator, but reaches not to the connector of the instrument cluster.
I have to take a look where it ends.

Actually it is a little cold outside... :(
So I went to the shop of a friend of mine on next Saturday.
There can I take a look on this and many other things, I have to do on this car. :D


Thanks ans regards...
72' F250 360, LWB, SportCustom, 4 on the floor.
1994 BMW 540i touring manual six speed.
2008 Ford S-Max 2,5T - powered by Volvo :-)
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