Two Electrical Questions

[Dr G]

Folks, I am rewiring my 56 F100 and have two questions:

I would like to illuminate an LED on the dash when the ignition is ON, but the engine is not running. I am thinking to use some type of voltage sensing switch, or maybe RPM sensing, as both paramters will change when the engine is running. But I've not come up with anything.

For the rear, my brake lights do double duty as turn signals. So if you have the turn signal activated while pressing the brake, like at a stop, then essentially I need to flash the brake light on and off. The only way I have figured out to make this work is with cascaded SPDT relays. It should work, but seems cumbersome. I wonder if there is a cleaner way to do it.

If anyone has input on either subject I am all ears. Thanks.

Gustave

[anthonys 69]

Most cars run an ignition on engine off light from the alternator it’s also the charging light the oil pressure also does the same thing.
What kind of steering column do you have on most cars that the brake lights and the turn signal are the same bulb, the power from the brake light switch goes through the turn signal switch. With out a schematic it will be hard to explain. The only wire that would go to the rear with out going through the turn signal switch would be for a third brake light. Talking brakes and turn signals. If you need help let me know I can email or fax you a schematic. Good luck.

[TnBlkC230WZ]

What type of column and blinker switch are you running? I can't think of a way to do it with a single pole relay. Even with a time delay device or relay would have issues in certain scenarios.

The blinker control is usually handled through the blinker switch. There will be two distinct circuits, one with a flasher in line. They both should go to the blinker switch. the blinker switch decides which of the two power sources go to the left and right bulbs. In GM cars (and I assume other makes), the emergency flasher circuit also passes through the blinker switch which is a third distinct circuit and second flasher.

I like the oil pressure switch to tell if the engine is running. It is pretty fool proof.

[Dr G]

Thanks guys. I am doing this rewire from scratch, including building the power control module (fuse box). The steering column is an Ididit. The switch in the column is just a switch as far as I can tell. Pull the turn signal stalk down and it completes the circuit between the 12V in and one of the output pins. Push the stalk up and it completes the circuit to another output pin. This switch sits downstream of the flasher relay, and connects the flasher to a load (the turn signal bulb element). The front driving lights have dedicated turn signal elements. The rear turn signal and brake light is done by a single element, with the second element in the bulb being the lower wattage tail light.

The alternator is single wire type. At least that is how I am using it. It is a Powermaster GM style and does have a three pin connector on it. Perhaps I can use that to my advantage. I do have an oil pressure transducer which I am using for an oil pressure gauge. I'm sure there are pressure switches I could use to trigger a light. I had not thought of that. I was fixated on using the difference in voltage created when the alternator starts to output current.

I have a sketch I drew up to figure out the turn signal brake light thing. I'll scan it and post it for anyone to look at.

[Dr G]

Here is the sketch:

https://static1.pt-content.com/images/pt/2011/11/lightsschematic2X3-1.jpg

The 12V signal from after the brake light switch is used to change the position of two SPDT relays (pink). The output of the turn signal is now used to turn one side of a second set of SPDT relays (green) on and off, which modulates the brake light to act as the turn signal, as long as the brake pedal is depressed.

Gustave

[anthonys 69]

you don’t need all that call ididit they'll send you a simple wiring diagram your column is already set up for brakes and turn signals no relay needed. When you get the diagram it really is simple. I just don’t have one at hand to send you I can get one tomorrow for you. Try this
http://www.google.com/url?sa=t&rct=j&q=ididit%20steering%20column%20wiring%20diagram&source=web&cd=2&sqi=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.ididitinc.com%2Ftech_instruct ions%2Fc_c_wiring_ps.html&ei=OVqvTr_RGIjjsQLVlf21AQ&usg=AFQjCNEvY4x00XrXJStrnCg14TDMFIujwQ

[TnBlkC230WZ]

I agree, the Idiot column should work without the relay. I believe they use GM switches, so you are golden. Your wiring diagram will not work as designed. Your brake circuit will always turn on the blinker relay (make pin 87 hot) and override the blinker side (pin 87a) which will only have power when the brakes are off and the blinker switch is on. Also, it looks like you are taking your brake power circuit to ground. You'll need a resistor there to prevent a short to ground. If you PM me, I can send you a Visio of your wiring needed with a GM switch with emergency flasher. It is about 4 Mbyte so it has to be emailed.


you don’t need all that call ididit they'll send you a simple wiring diagram your column is already set up for brakes and turn signals no relay needed. When you get the diagram it really is simple. I just don’t have one at hand to send you I can get one tomorrow for you. Try this
http://www.google.com/url?sa=t&rct=j&q=ididit%20steering%20column%20wiring%20diagram&source=web&cd=2&sqi=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.ididitinc.com%2Ftech_instruct ions%2Fc_c_wiring_ps.html&ei=OVqvTr_RGIjjsQLVlf21AQ&usg=AFQjCNEvY4x00XrXJStrnCg14TDMFIujwQ

[Dr G]

you don’t need all that call ididit they'll send you a simple wiring diagram your column is already set up for brakes and turn signals no relay needed. When you get the diagram it really is simple. I just don’t have one at hand to send you I can get one tomorrow for you. Try this
http://www.google.com/url?sa=t&rct=j&q=ididit%20steering%20column%20wiring%20diagram&source=web&cd=2&sqi=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.ididitinc.com%2Ftech_instruct ions%2Fc_c_wiring_ps.html&ei=OVqvTr_RGIjjsQLVlf21AQ&usg=AFQjCNEvY4x00XrXJStrnCg14TDMFIujwQ
Yes, you are indeed correct. The way I drew it activating the brake light switch will open circuit the brake lights if the turn signal is not active.

In any case, I PM'd you my email address.

Thanks folks,

Gustave

[Dr G]

I did some scratching around on the turn signal brake light thing. Some folks recommend using a type of trailer adapter to allow the brake light filament to also function as a turn signal. But one chap on a different forum had the answer I was originally looking for, which is how to wire this up when the turn signal switch is a simple 2 position switch. I've added his description to the pic:

https://static1.pt-content.com/images/pt/2011/11/turnsignalschematic-1.jpg

I now realize that the GM turn signal switch is a bit more sophisticated than I first thought. Ididit was not able to help much. They sent me a wiring diagram for a VW, but I could not see how to use any of it. I do have the original Ron Francis wiring diagrams, as that is what came in the truck when I bought it, with a GM turn signal switch (as it had a Pontiac Bonneville steering column then). I'll look at those tonight and see what I learn.

Gustave

[anthonys 69]

Ok I didn’t get your pm but I have a wiring diagram for you. if you can give me your e mail ill send it to you. it’s a wiring diagram of a 85 Chevy el Camino. it’s the same and it even has the same color wires. it wont copy and paste !!!!!

[TnBlkC230WZ]

I emailed the wiring diagram. The two problems I see with your drawing are with the front blinkers and the two purple relays. The way you are wired, the front blinkers will illuminate when the brake pedal is pressed. The two purple SPDT relays control power to the brake circuit and to the blinkers. The relays will cycle on and off when the blinker and the brakes are on simultaneously causing both front and rear blinker blubs to illuminate continuously.


Ok I didn’t get your pm but I have a wiring diagram for you. if you can give me your e mail ill send it to you. it’s a wiring diagram of a 85 Chevy el Camino. it’s the same and it even has the same color wires. it wont copy and paste !!!!!

[anthonys 69]

I emailed you a wiring diagram too let me know if you got it and if it helps and if I can help you any further. Good luck.

[TnBlkC230WZ]

The SP4T relays will do the trick. You don't really need to run your parking lights through them though. The Ididit web site leaves a lot to be desired. It is not much help with the wiring. Looking at the pics, it looks like a GM connector. Can you post a pic? I'm curious as to the wiring colors and if they match the GM wiring colors.

Hopefully one of the Ididit experts will chime in.



I did some scratching around on the turn signal brake light thing. Some folks recommend using a type of trailer adapter to allow the brake light filament to also function as a turn signal. But one chap on a different forum had the answer I was originally looking for, which is how to wire this up when the turn signal switch is a simple 2 position switch. I've added his description to the pic:

https://static1.pt-content.com/images/pt/2011/11/turnsignalschematic-1.jpg

I now realize that the GM turn signal switch is a bit more sophisticated than I first thought. Ididit was not able to help much. They sent me a wiring diagram for a VW, but I could not see how to use any of it. I do have the original Ron Francis wiring diagrams, as that is what came in the truck when I bought it, with a GM turn signal switch (as it had a Pontiac Bonneville steering column then). I'll look at those tonight and see what I learn.

Gustave

[anthonys 69]

You don’t need the relays in the diagram above. Gm has used the wiring diagram I sent you for years the ididit column is wired the same way. It works so don’t over think it!!!!….. There is the fact that you came up with your own way of doing it…. So what ever you decide… good luck

[Dr G]

You don’t need the relays in the diagram above. Gm has used the wiring diagram I sent you for years the ididit column is wired the same way. It works so don’t over think it!!!!….. There is the fact that you came up with your own way of doing it…. So what ever you decide… good luckSure, understood. But I spent a bit of time trying to figure out how to make this work from scratch, and got it wrong. So I was pleased to see that someone else had indeed figured out how to do it with a simple (non-GM) switch. And I thought others might be interested, now or in the future.

I will, however, use the GM switch in the Ididit Column. Now that I understand the pin-out definitions. Here is a copy of what I was sent by Anthonys 69 which shows the wire colors on a GM turn signal switch and how it should be wired up to the flasher relays and brake light switch.

Thanks to all.

Gustave

https://static1.pt-content.com/images/pt/2011/11/GMturnsignalswitchwire-1.jpg

[anthonys 69]

Hi Gustave. I’m glad I was able to help. If you need anything else just let me know. You must be a little better than me with computers. I couldn’t get that thing to show on this web site like you did . Good luck