Posted By: Tony H
12V switched off ignition - 07/20/09 08:32 PM
Is it the brown wire off the Ignition that is the Switched 12V? '68 Barracuda
I would like to run Toggle switches that are energized only when the car is 'On'.
Brown runs to 'Q' on teh bulkhead connector that runs to the Ignition Ballast among other things...
The diagram I have is way hard to read
Posted By: NachoRT74
Re: 12V switched off ignition - 07/20/09 08:42 PM
brown wire is only ON directly from ign switch when starting up, rest of the moments is powered just because the ballast resistor works like a splice on it ( being feeded by the blue wire from ign switch ), but not anymore powered directly by ign switch
Posted By: Tony H
Re: 12V switched off ignition - 07/21/09 12:25 AM
OK,
So that wouldn't be the best place to grab voltage from to feed Electric radiator fans and Coil Voltage and Electric fuel pump.. I doubt the wire gauge ( blue wire) can handle it.
Any suggestions for grabbing 12V that is only on when ignition is on?
Helping a friend with his Hemi '68 Cuda. Planning on Toggle switches to turn on these things. Some will be 12 Volts direct and some we want to shut off when car is turned off.
Posted By: HealthServices
Re: 12V switched off ignition - 07/21/09 12:38 AM
You can still use the blue wire, just use it as a signal wire for a relay and then get your power for the relays at the starter relay.
Posted By: HealthServices
Re: 12V switched off ignition - 07/21/09 12:49 AM
you still hook up the coil wire to the Brown at the resistor (this is true only if you are still using the resistor).
Power to the Fan and the Fuel pump is thru a relay and powered from the from the large wire at Starter relay.
The signal is from the Blue Wire going thru toggle switches feeding the signal wire on each relay.
The fan and the pump only work with the key on.
Posted By: HealthServices
Re: 12V switched off ignition - 07/21/09 12:57 AM
With a typical Bosch relay,
- 85 will go to the switch
- the other end of the switch will go to the Blue Wire
- 87 will go to the + fan (or to the fuel pump)
- 30 will go to the large post on the starter relay. I would put a fuse in between somewhere here.
- 86 will go to ground
- fan (or fuel pump) ground will go to ground.
The above will only work when the ignition is switched on.
If you want constant power to the switches without regard to the ignition with a typical Bosch relay,
- 85 will go to the switch
- the other end of the switch will go a good ground
- 87 will go to the + fan (or to the fuel pump)
- 30 will jump to 86 and then to the big post on the starter relay
- fan (or fuel pump) ground will go to ground.
Posted By: Tony H
Re: 12V switched off ignition - 07/21/09 04:10 PM
thanks all.
I was trying to avoid yet another relay. As reliable as they are, it's just an added headache if I have problems in the future. I guess one 50A relay coming off the Blue wire to run the entire 'Switched' Panel of toggle switches wouldn't be that bad.
Posted By: HealthServices
Re: 12V switched off ignition - 07/21/09 04:52 PM
The wiring on these old cars just plain sucks. Tapping power will generally mean some type of wiring failure in the future
Posted By: Anonymous
Re: 12V switched off ignition - 07/21/09 05:28 PM
Quote:
thanks all.
I was trying to avoid yet another relay. As reliable as they are, it's just an added headache if I have problems in the future. I guess one 50A relay coming off the Blue wire to run the entire 'Switched' Panel of toggle switches wouldn't be that bad.
Depends, are the switches turning on RELAYS or the LOADS directly? If the switches are merely turning on relays, there's no need to use a relay to feed the switches.
Frankly, the BEST way to feed a buss for all big loads, fans, stereo, etc, is probably to get a "continuous duty solenoid" and turn it on off the ignition, then feed everything else off that.
The problem with adding stuff on these cars is several:
The ignition switch and connector has it's limits
The bulkhead connector is a problem
The wiring is not large enough
Posted By: Tony H
Re: 12V switched off ignition - 07/22/09 05:21 PM
[Depends, are the switches turning on RELAYS or the LOADS directly? If the switches are merely turning on relays, there's no need to use a relay to feed the switches.
Frankly, the BEST way to feed a buss for all big loads, fans, stereo, etc, is probably to get a "continuous duty solenoid" and turn it on off the ignition, then feed everything else off that.
The problem with adding stuff on these cars is several:
The ignition switch and connector has it's limits
The bulkhead connector is a problem
The wiring is not large enough
It appears I need a "big" relay to do the switching but after that I was hoping to switch direct to Pump and fans, etc. I have some high amperage military switches that should last forever. The battery is in the trunk so I will either run a 6 awg from the trunk to under the dash OR, as recommended, grab and run a shorter wire from the Starter Relay to power up the High current side of the Relay.
A big solenoid. Hmm, I wonder if you can keep a Starter relay energized? I bet it wasn't designed for continuous power. I have a Ford Starter relay kicking around, I think I'll throw 12 volts on that and see how hot it gets.
Posted By: Anonymous
Re: 12V switched off ignition - 07/22/09 08:39 PM
Quote:
It appears I need a "big" relay to do the switching but after that I was hoping to switch direct to Pump and fans, etc. I have some high amperage military switches that should last forever. The battery is in the trunk so I will either run a 6 awg from the trunk to under the dash OR, as recommended, grab and run a shorter wire from the Starter Relay to power up the High current side of the Relay.
A big solenoid. Hmm, I wonder if you can keep a Starter relay energized? I bet it wasn't designed for continuous power. I have a Ford Starter relay kicking around, I think I'll throw 12 volts on that and see how hot it gets.
You absolutely CAN NOT GUARANTEED USE a starter relay, they WILL burn up. Buy what is called a "continous duty solenoid"=='s why they're called that.
You have a good heavy live cable from the trunk to the starter? Then pick up your power feed right from the starter, run that right to your continuous solenoid preferably through a fuse link to handle all loads--it's just for dead short possibilities.
Posted By: HealthServices
Re: 12V switched off ignition - 07/23/09 12:30 AM
I still think using relays is still the best option. Cost less too. Putting a "continuous duty solenoid" ($50 or more) or a starter relay is one potential problem in itself. Letting the battery voltage go thru the switch and to the load can be another problem, especially if the switch does not have the capacity handle the load.
Posted By: Anonymous
Re: 12V switched off ignition - 07/23/09 12:56 AM
Quote:
I still think using relays is still the best option. Cost less too. Putting a "continuous duty solenoid" ($50 or more) or a starter relay is one potential problem in itself. Letting the battery voltage go thru the switch and to the load can be another problem, especially if the switch does not have the capacity handle the load.
I think that's a possibility, just based on what you and I read into his description. It sounded to me like he has an awful lot of hi-amp stuff to run, and that a continuous duty solenoid, fed either by a master toggle or the key would be one way to feed the "hi amp buss" and have individual relays/ switches off that buss.
The thing is, it sounds like he DOES have some hi amp stuff that SHOULD NOT go through the key. Obviously you can use the key to trigger an almost unlimited amount of relays