What options are there for key on power

[prayers1 153]

I'm looking to get power other than the fuse box. I've read some where's that you can use power for key on only items via the solenoid, but I don't know if that's true.

 

I've been told to run a separate fuse box, but that would only work if the item has an on/off switch. The items I'm looking at need the key on only to get power.

 

I'm not much of an electrical guru so I need your opinions on what to do.

 

I'd like to get key on power to the following:

Alt Gauge

Trans temp gauge

Trans overdrive switch

Tachometer

 

Thanks!

[miketyler 15]

I found a source under the hood and was discussed here in a thread somewhere. I want to say it was the white female connector there at the engine side of the firewall. I believe I found this when I was looking for a keyed power source for relays running SPAL electric fan.

[RogerC 136]

I've been told to run a separate fuse box, but that would only work if the item has an on/off switch.

Use a relay to switch it on/off with a switched power source. Size components appropriately.

[sportsroof69 13]

Use a relay to switch it on/off with a switched power source. Size components appropriately.

 

This. You can run what ever you want off the key, as long as you power it with a relay.

[Midlife 814]

There are a number of options, but the one that is always available on both 69 and 70's, tach and non-tach, is the green/red or red/green (sometimes red/yellow) on the ignition plug. Just splice into that wire and you're good to go.

[prayers1 153]

The wire from the ignition plug. where is it's source? Is it from the fuse box??

I hope not. I'm trying to avoid over use of that box.

 

I don't know much about relays. Please tell me what type of relay to use, Where to get it and how to install.

 

IMO, I think you tap into a power source, then to a relay then to what your powering.

How does it know when to go on?

I have to power 3 items. Can I use one relay for that.

 

I need a little more help here before I start cutting into wires.

Thanks thus far!

[prayers1 153]

I've been looking at relays on the internet and to me they all seem to need a trigger point such as a on/off switch.

 

I don't want to sit there and start switching things on, I want to turn the key and then have them turn on.

[Midlife 814]

The wire comes from the ignition switch connector, controlled directly by the keyed ignition. You use that wire as the trigger for the relays.

[LoneWolf2U 136]

Relays are a simple off/on power distributor for heavy loads.

it uses a lower power load to switch them on to supply power to the larger amp demand items.

 

On my truck for example,

It has been set up for towing with a high amp power line(8ga) for winch/batt and acc usage.

I installed a relay for the 60w work lights I use that are mounted under the bumper.

Using a relay allows me to draw the load power at the rear near the lamps and only need a 16ga wire running to a switch on the dash for controling them.

 

You can use 1 relay for the trans/tach/Od switch power source.

This will have 1 wire connected to the ign switch that triggers the relay.

The alt charge guage must be wired completely different.

[miketyler 15]

As Mach 1 said, generally relays are used to control higher amp loads like headlights, fans, high watt amps, etc, none of which I believe you mentioned unless the trans switch is carrying a large load. I thought either the green/red or the white connector were good options for a "turn-key" switched power source.

 

How about the optional yellow 3 female bullet connector or maybe you already have it? It includes a clip with a lead and 3wire connector for adding up to three switch sources and its installs directly to the OEM fuse box. Consists of the busbar and the wire 3femail connector

 

Busbar:

 

accessory connector

Edited June 8, 2014 by miketyler

[prayers1 153]

Thank you everyone for the explanation, it's been very helpful.

 

Here's a diagram I got from the internet- Is this what were talking about.

 

Tell me if I'm right or not,

The trigger point will be off of the ignition wire.

The power source will be from the Accessory Post.

Everything else seems to be self explanatory.

 

Where do I get power for the alt mech. gauge, prior to this, I just used a spot on the fuse box?

Where do I get power for the electric choke?

 

Does anyone have a picture of the wire from the ignition source. I don't want to use the wrong one by accident.

 

[prayers1 153]

Mach1Rider, it just dawned on me after reading your post that I have lying around a complete wiring kit for 4x4 off road lights.

 

Here's a copy of the wiring diagram. I'm confused at this point, since the first diagram I posted shows different wiring locations on the relay then the Off Road wiring kit.

 

Using the Off Road wiring kit, how would I wire it up for mine.

 

I still need to be certain on which wire I use from the ignition????????

 

[miketyler 15]

Did you already have the busbar I mentioned? That is the cleanest was to add a new switched circuit. You simply screw it on to your 69-70 the fusebox, insert a fuse and connect an accessory BUS like this one from Delcity that uses mini fuses.

 

[prayers1 153]

In this diagram, is it the green/red wire #904, that I splice into for the trigger point?

 

[miketyler 15]

If you are convinced you need to relay the loads, and decide you want to fuse them as well this looks like a great part to do all of that including a circuit breaker to protect the main feed going to it:

 

[prayers1 153]

Thanks Mike, that does look like a good set, but the loads I'm going to draw wouldn't require that much circuitry. I'm looking to avoid my old school habits of sticking wires into the fuse box. I just don't want to overload the circuit.

 

IMO, I think one relay to power the O/D switch, Trans temp gauge and tach is adequate.

 

I would like to wire it to a distribution block as in the first picture, but I just need someone to confirm which wire goes where off the relay.

 

Also, I still need to confirm that green/red wire is the correct trigger wire.

[LoneWolf2U 136]

post 86- to 904 ign wire key on source

post 85 - ground

post 87 to acc for power

post 30 from batt power source

 

for what your trying to operate, I would run one wire from the fuse panel acc post to the temp/od/tach power terms.

This will have a key on only power source. KISS it.

Edited June 8, 2014 by Mach1Rider

[prayers1 153]

Thank you!

 

How about a source for the mech Alt gauge and electric choke.

[LoneWolf2U 136]

+ side wire from choke to STA term of alt, this is best for choke operation as Ford used this for years.

Alt guage is differant, depends on if its a voltage read or amperage read guage as each has differant connections.

[prayers1 153]

I'm running a one wire set up using a GM alt. I have one wire from the alt. to the Pos. Battery side of the Solenoid, other than that I'm grounding the alt. to the block.

I do not know hwat you mean " STA term of alt".

So, how would I wire the choke?

 

The OEM wires to the Alt and voltage regulator are not in use, they are just hanging there.

 

Sorry, I meant to say Mech volt meter gauge, not "mech Alt gauge". In the past I just wired it to the fuse box. I'm thinking there must be a better way.

[prayers1 153]

Before I commit to this, I want to make sure of a few things.

 

The whole object of this thread is to take away all of the wires I was plugging into the fuse box and make a more simple junction box to power a few items w/ the key on.

 

Today I discovered that the Assy Post is in fact activated by key on, I thought that it always had power with the key off. That's why I thought it was a good ideal to use a relay and the ignition wire as the trigger, but since the Assy Post is turned on by the Key on mode then do I really need to put a relay in. I do not think all of the items listed below draw a lot of current.

 

So, would it be ok just to run a fused wire from the Assy post to a distribution box and from there I can power:

Overdrive switch.

Trans temp gauge

Tach

Electric Choke

 

Am I asking too much from the Assy Post.

 

Please Advise!

[Midlife 814]

I manufacture and thus sell those Buss Bar and connectors for the ACC fuse box for $20 plus shipping if you are interested.

http://midlife66.com/harnesses