LED install(PIC'S) - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BobbyK · 02-16-2005, 04:31 AM

I installed a blinking red LED today.
69 Short Fleet(Doug) and I were discussing how to do this.So this is how it's done.

I know,I know...it's no substitute for a REAL alarm but this was real CHEAP and only took a couple hr's to do.

So here we go.

I started with a "blinking " red LED.It has the Blinking circiut and resistor built in so all you have to do is connect the "Anode" to a +12v source and the "Cathode" to ground.This was about $6.00 at my local electronics store(not Radio Shack)

Now that I had the flashing LED,the trick is to get it to flash while the truck is off and stop flashing when you turn the ign. on.

Well to accomplish this you simply use a common automotive relay.
I used a Single Pole Double Throw(SPDT) relay rated at 30amps.Way too much for my application but that's what I had on hand.Any amp rated relay will work though.
The actual draw that this circuit will use is in the mili-amps,not amps.

Here's the relay I used.Again about $5.00 at my local electronics shop.

So the next step was to decide where I wanted it mounted.
I did NOT want to drill into the face of the dash or the dash area between the front window and the dash pad,but that is where it would be MOST visable.

So I removed the drivers side air duct bezel and checked my clearances.Luckly things JUST fit.
I drilled a hole then mounted the LED retainer in the bezel.

I then slid the LED into the bezel and gave it a test.

Before installing the bezel back into the dash I "hot glued" the LED in place.

Now hooking up the LED with the relay was done exactly the same as you'd make the connections for ANY relay application.The ONLY difference is that I used the 87a terminal on the relay to connect to the LED.

The 87a terminal is "HOT" when the relay is not energized(relay not being triggered)
Normally the 87 terminal is used and becomes "HOT" when the relay is energized.

But in this application you want the operation of the relay to be opposite.

So this is how the relay is wired.

Here is the switched source I used for the 86 terminal.This terminal on the fuse box is only "HOT" when the ign. is on.
There is no power when the ign. is off or in the ACC. position.
I'm pointing to it with the tip of my circuit tester.

Then just find a constant 12v+ source and connect it to the 30 terminal.

Here it is back in the dash.

You really can't tell from the next few pic's but this LED is BRIGHT!
It blinks about once per second.

Anyhow,that's about it.

I now have a blinking red LED on my dash that will not protect my vehicle what-so-ever.
Thanks for listening

69 Short Fleet · 02-16-2005, 07:34 AM

Great thread Bob!

crispy · 02-16-2005, 10:10 AM

thanks for keeping us (me) informed BobbyK. i'm a dunce when it comes to wiring so every little bit helps... thanks again.

Smokie55 · 02-16-2005, 10:37 AM

That has to be one of the coolest articles ever. I mean most folks will see it as a waste of money. but I think it is brilliant and thanks for walking us dummies through it.

JayDubBlazer · 02-16-2005, 11:51 AM

Cool that is a good idea

bouncytruck · 02-16-2005, 12:36 PM

Good idea and great placement! My wife's '04 Explorer has a blinking light on the dash (it is actually connected with the security system) and I've thought about putting something like that on my dash too. I couldn't bring myself to drilling a hole in the dash and I hadn't thought about putting it in the defrost vent.

*Gee_Emm* · 02-16-2005, 07:49 PM

Nice, I added this to the FAQ section.

What is next months article?

bagged74 · 02-16-2005, 09:33 PM

looks great, and will warn some thieves away. The only thing is the relay is probably not necessary. You can connect the cathode to the ignition wire at the switch. This wire will rest at ground wehn the switch is off. when the switch is on the light will not flash because it will see +12v on both sides of the diode.

FRENCHBLUE72 · 02-16-2005, 11:19 PM

Nice step by step have you put it in the F.A.Q. section...

*Gee_Emm* · 02-16-2005, 11:25 PM

Quote:

Originally Posted by FRENCHBLUE72

Nice step by step have you put it in the F.A.Q. section...

I sent a copy to that forum

LUV2XCLR8 · 02-17-2005, 07:23 PM

DAMN, SOMETHING ELSE TO ADD TO MY LIST

WHAT SIZE DRILL BIT DID YOU USE FOR HOLE

BobbyK · 02-17-2005, 07:48 PM

I used a step drill bit.
I think the hole is either 9/16" or 5/8",I didn't pay attention to that when I was doing it,sorry.

Gee_Emm,

Quote:

What is next months article?

lol,that's funny

bagged74,
I have since been made aware of that way to wire it up,much simpler yes!

02-16-2005, 04:31 AM	#1
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,772	Cheap security - LED install(PIC'S) I installed a blinking red LED today. 69 Short Fleet(Doug) and I were discussing how to do this.So this is how it's done. I know,I know...it's no substitute for a REAL alarm but this was real CHEAP and only took a couple hr's to do. So here we go. I started with a "blinking " red LED.It has the Blinking circiut and resistor built in so all you have to do is connect the "Anode" to a +12v source and the "Cathode" to ground.This was about $6.00 at my local electronics store(not Radio Shack) Now that I had the flashing LED,the trick is to get it to flash while the truck is off and stop flashing when you turn the ign. on. Well to accomplish this you simply use a common automotive relay. I used a Single Pole Double Throw(SPDT) relay rated at 30amps.Way too much for my application but that's what I had on hand.Any amp rated relay will work though. The actual draw that this circuit will use is in the mili-amps,not amps. Here's the relay I used.Again about $5.00 at my local electronics shop. So the next step was to decide where I wanted it mounted. I did NOT want to drill into the face of the dash or the dash area between the front window and the dash pad,but that is where it would be MOST visable. So I removed the drivers side air duct bezel and checked my clearances.Luckly things JUST fit. I drilled a hole then mounted the LED retainer in the bezel. I then slid the LED into the bezel and gave it a test. Before installing the bezel back into the dash I "hot glued" the LED in place. Now hooking up the LED with the relay was done exactly the same as you'd make the connections for ANY relay application.The ONLY difference is that I used the 87a terminal on the relay to connect to the LED. The 87a terminal is "HOT" when the relay is not energized(relay not being triggered) Normally the 87 terminal is used and becomes "HOT" when the relay is energized. But in this application you want the operation of the relay to be opposite. So this is how the relay is wired. Here is the switched source I used for the 86 terminal.This terminal on the fuse box is only "HOT" when the ign. is on. There is no power when the ign. is off or in the ACC. position. I'm pointing to it with the tip of my circuit tester. Then just find a constant 12v+ source and connect it to the 30 terminal. Here it is back in the dash. You really can't tell from the next few pic's but this LED is BRIGHT! It blinks about once per second. Anyhow,that's about it. I now have a blinking red LED on my dash that will not protect my vehicle what-so-ever. Thanks for listening __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE Last edited by BobbyK; 02-16-2005 at 04:37 AM.

02-16-2005, 10:10 AM	#3
crispy '71 Chevy Blazer Join Date: Jan 2005 Location: San Leandro, CA (near Oakland) Posts: 96	thanks for keeping us (me) informed BobbyK. i'm a dunce when it comes to wiring so every little bit helps... thanks again. __________________ '71 K5 Blazer (new project / daily driver) "If you are not working to improve the situation, you have no business complaining"

02-16-2005, 10:37 AM	#4
Smokie55 Registered User Join Date: Oct 2002 Location: Wylie, TX Posts: 141	That has to be one of the coolest articles ever. I mean most folks will see it as a waste of money. but I think it is brilliant and thanks for walking us dummies through it. __________________ -- Will Evans -- 1955 Short Step "Sweet Pea" - Family heirloom. 1969 Suburban "Otis" - 396/TH400 - Dallas Ambulance - 1972 K5 blazer "Rusty" - 400/TH350/NP205 - Yeah it's big alright!! - Founding Member of Southern Bowties Club -

02-16-2005, 11:51 AM	#5
JayDubBlazer go cyclones Join Date: Jun 2003 Location: Ames, IA Posts: 1,883	Cool that is a good idea __________________ Wes PROJECT OLE GREEN 1972 Blazer 4X4 350/700R4 2017 Silverado LT

02-16-2005, 12:36 PM	#6
bouncytruck SKINNY TIRES RULE! Join Date: Sep 2001 Location: Bothell, WA Posts: 11,038	Good idea and great placement! My wife's '04 Explorer has a blinking light on the dash (it is actually connected with the security system) and I've thought about putting something like that on my dash too. I couldn't bring myself to drilling a hole in the dash and I hadn't thought about putting it in the defrost vent. __________________ bouncytruck 1972 K5 The Hauler 1994 K1500 Suburban The Daily2010 Kia Soul Wife's Ride2014 Fiat 500L

02-16-2005, 07:34 AM	#2
69 Short Fleet Registered User Join Date: Nov 2002 Location: Kelowna B.C. Canada Posts: 1,086	Great thread Bob!

02-16-2005, 07:49 PM	#7
Gee_Emm Account Suspended Join Date: Sep 2000 Posts: 3,991	Nice, I added this to the FAQ section. What is next months article?

02-16-2005, 09:33 PM	#8
bagged74 its just $$$$$ Join Date: Jul 2003 Location: OK Posts: 2,078	looks great, and will warn some thieves away. The only thing is the relay is probably not necessary. You can connect the cathode to the ignition wire at the switch. This wire will rest at ground wehn the switch is off. when the switch is on the light will not flash because it will see +12v on both sides of the diode.

02-16-2005, 11:19 PM	#9
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,606	Nice step by step have you put it in the F.A.Q. section... __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..

02-17-2005, 07:23 PM	#11
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,468	DAMN, SOMETHING ELSE TO ADD TO MY LIST WHAT SIZE DRILL BIT DID YOU USE FOR HOLE __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Tow Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T



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