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Hi guys, I am installing some aftermarket gauges and i am tapping into the yellow 3 connector plug under the dash.
However I am showing less than 12v 11.4 or so at the plug.
Does this mean I have a power draw somewhere? Or is this to be expected with resistance?
My battery has been unused for several months and is only showing the battery at 12.3v while hooked up to the charger. I will test again later when it has time to charge.
I am a wiring idiot so use small words and complete sentences.
That being said please forgive my ignorance when I ask the following:
Can I use the same 12v source to power all the gauges?
My gut says no on this one.
And can I use the same grounding location for all the gauges?
My gut says yes on this one.
To tell how much voltage the battery is providing, you have to test it off the charger, otherwise you're reading the additional voltage provided by the charger. If your battery is, indeed, testing at 12.3 volts and you have 11.4 at the source, you have resistance somewhere in the circuit. In this case the wiring may be severely oxidized or corroded. Your gauges may still work, but that doesn't solve the former issue. You can ground all of your accessories to a common ground...one that already exists, or clean metal somewhere and a "toothed" lockwasher for good contact. You can also use the common source for your 12 volt power (within reason), it's all coming from the same source, so it wouldn't matter how many different wires you ran off the ignition terminal/wiring loom, or if you connected to a common wire. It's more a matter of cleanliness/neatness of the wiring that you run to your gauges.
I believe those are 2 NONE keyed power sources. Meaning constant 12V 1. being the glove box 3/1 yellow plug, branches off and leads to the cig lighter and glove box light 2. behind the headlight switch area 3/1 yellow plug tapped into for dome light power.
Also get the power for the gauge lights not exactily from the headlight switch wiring. Or at least do it carefully.
I've always tapped into the Blue w/red wires for the instrument/dash illumination. Either at the headlight switch, or out at one of the branches.
But modern gauges often use LED lighting which is not dimmable with the old rheostat in the switch. Very annoying!
There are some dimmer dials made specifically for new gauges though. Check with the manufacturer.
the 3 to 1 connectors are switched 12v ?can it be used to trigger a relay and get power directly from the battery?
are all 3 terminals on the 3 to 1 used ? or might there be one spot open?
I believe the yellow 3/1 plugs are constant 12V and NOT 12V keyed power. On the glove box sided one the cig lighter is split off the glove box light connector, and it should have 2 ports open. The one behind the headlight area should have one used for the dome light and then 2 open.
I believe the yellow 3/1 plugs are constant 12V and NOT 12V keyed power. On the glove box sided one the cig lighter is split off the glove box light connector, and it should have 2 ports open. The one behind the headlight area should have one used for the dome light and then 2 open.
But again I am pretty sure they are CONSTANT 12V.
Not to muddy the waters, but I just hooked something up to my yellow 3/1 conenctor (behind the headlight switch, black wire w/green stripe) last weekend. Appears to be same connector as pictured above. When I tested it, it was switched power in my truck. 12v with key on. None with key off. 77 f250 reg cab long box.
Thanks! They are the summit brand electric gauges pretty reasonably priced too.
Originally Posted by 1TonBasecamp
I've always tapped into the Blue w/red wires for the instrument/dash illumination. Either at the headlight switch, or out at one of the branches.
But modern gauges often use LED lighting which is not dimmable with the old rheostat in the switch. Very annoying!
There are some dimmer dials made specifically for new gauges though. Check with the manufacturer.
Paul
Would that branch include the bulb for the radio as well?
Originally Posted by _mtnbiker
Not to muddy the waters, but I just hooked something up to my yellow 3/1 conenctor (behind the headlight switch, black wire w/green stripe) last weekend. Appears to be same connector as pictured above. When I tested it, it was switched power in my truck. 12v with key on. None with key off. 77 f250 reg cab long box.
No muddy waters to me, if the 3/1 is found to be different than what I have or understand, then we know even more for sure, correctly. I went back and looked at the pic I even posted and it says the one behind the headlight switch is a 12V KEYED CONNECTOR, so that makes sense with your findings. And I was wrong, simple enough to say that.
No muddy waters to me, if the 3/1 is found to be different than what I have or understand, then we know even more for sure, correctly. I went back and looked at the pic I even posted and it says the one behind the headlight switch is a 12V KEYED CONNECTOR, so that makes sense with your findings. And I was wrong, simple enough to say that.
All good. My thought was that I might be causing confusion because it could be different in different years of trucks. I didn’t even know that connector was there. Pretty smart move to install that connector by ford. I stumbled upon it when looking for a switched 12 volt source that wouldn’t require too much work. Best part of it was that it appears to be one of the only wires in my whole truck that hasn’t been cut up by the p/o.
You do have BOTH of them located correct? Maybe since the one behind the headlight switch is one wire it is for sure a key hot 12V and the one behind the glove box (2 wire) is constant 12V? I dug the one out of my parts rig for its pic. The last 2 are its placement behind the glove box (in another rig) with the cig lighter and glove box light connector.
I am for sure using the one behind the headlight switch and it is only 12v with the key on or in the acc position. I have messed with the one behind the glove box.
Is the blue wire the wire that goes to the lightbulb for the radio?
If so I plan on tapping into that wire to make the gauges dimmable.
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