Originally Posted by Merlin1
I was talking to some folks and they suggested using a relay.
Anyone have any idea if the following would work?
It will probably work, assuming the dash lights are turned up high enough to close the relay. Anything above 6 volts should be sufficient, I think. The point is that your neon is not going to dim with your dash lighting; it'll be either on or off, depending on whether your dash lighting voltage is turned up high enough to trigger the relay. I would make your relay connection off the brown wire on your headlight switch instead, which is your exterior lighting circuit, and will deliver a full 12-14 volts to your relay instead of a variable voltage from the dimmer.
You can see various wiring issues handled via use of these same relays (both 4-pin and 5-pin versions) in diagrams from the remote starter installation manuals at http://www.bulldogsecurity.com/pdf/RS102_112_122.pdf
if that helps.
Anyhow, paraphrasing what you were told:
30 pin: pos neon wire -- This will be power from the relay to your neon
85 pin: pos wire from dash lights -- This will trigger the relay
86 pin: ground -- Ground for the relay circuit
87 pin: fused 12v constant -- Power feed for the neon
87a pin: fused 12 constant on a switch -- Alternate power feed for the neon (see below)
This way they will turn on when your dash lights turn on or if they are off you can turn them on with a switch.
When the relay is off (unpowered), there is a closed circuit through it, going in pin 87a and coming out pin 30. That'* why you can hook up a switched power supply to your neon through that pin. When the relay is triggered, pin 87a is turned off and pin 87 is turned on, or in other words, when the relay closes, its main input switches from whatever is coming in on pin 87a to whatever is coming in on pin 87. In either case, its output is pin 30, where you'll hook up your neon. (Yes, you can wire those pins the other way around, too, so that output goes one place when the relay is off, and another place when the relay is on.)
One thing I should point out is that this is a 5-pin relay, which includes that pin 87a for a "normally closed" circuit. You don't absolutely need that fifth pin; if you're not planning to add a manual override switch for your neon, you don't need it at all and a 4-pin relay will do instead. Radio Shack has both 4-pin and 5-pin relays available; the 4-pin is part #275-226 and can be found at their website ( http://www.radioshack.com
). The 5-pin is pictured on the BulldogSecurity website here: http://www.bulldogsecurity.com/images/Model757.jpg
It'* basically the same thing, either with or without the pin 87a in the middle. Any good electrical supply place should have them.
If you put a switch before the 85 pin then you can still have them off when the lights are on.