Need a little wiring help - LED for TC lock-up switch

[mwilson]

Scott,



I think what Cerb is telling you is to wire it like this. Please forgive my poor photo shop skills... ...

Mike.

 

[BigPapa]

I was thinking about this while taking the kids to school and realized that very thing.



Question, what does the resistor do?

 

[cerberusiam]

I defer to Mike's artistic skills, he nailed it.

The resistor takes the load out of the system so it won't kill the LED, and, protest it from a dead short in the wiring harness. A dead short should pop the trans relay, but, a partial short will sit there and melt wires in the harness. The resistor will blow under a heavy load and break the circuit.

The LED is only rated at 15 milliamps, 1 amp will cause it issues. LED works by passing a current thru a diode that glows. The diode may burn out or get too hot or have thermal protection built in to where it won't light correctly but the current will still pass thru.

 

[BigPapa]

Gotcha.



A couple more questions.



Should I be concerned that the wires coming out of the LED being so small? Any danger there?



And, isn't this a resistor?



#ad




If it is, do I still need another one?



Thanks!

 

[cerberusiam]

Since the load should be pretty small the wire size should not a big deal.

The LED likely has a resistor in it to provide some type of resistance to the diode but not sure if that will provide much of any in the circuit, or any protection.

 

[GW208]

I know you said that you didn't want to tear the pillar pod out again but I really think that will save you some time and headaches. You need to take that LED and hook it straight across your battery and make sure it works properly.

 

[BigPapa]

Thanks GW. Did that yesterday. Actually replced it and checked the new one before install.

 

[GW208]

So it works fine hooked straight across the battery? If that's so, then there is no reason it wouldn't light up the way you had it wired originally because you were doing the same thing, 12 volts on one side of the light and ground on the other. Your post 15 is a little confusing when you say you had 12 volts for a minute and then nothing? The light should have been on as long as you were touching the ground wire of the LED direct to a good ground. I'm starting to suspect your 12 volt supply to the light if it didn't work when you did that. Good luck, it will be interesting to see what you find.

 

[Partyat33]

You cannot have two 12 volt devices in series on a 12 V circuit. Period

 

[BigPapa]

OK cerb. What about what Party says? Your opinion?



I went to get a resistor and they had 1 watt but only had 10 and 100 ohm. I got both. Which should I use?



Thanks.

 

[BigPapa]

I'm starting to suspect your 12 volt supply to the light. Good luck, it will be interesting to see what you find.

The 12V supply is now gone. No doubt my posts are confusing because I AM confused! If I could only find my copy of "Wiring and Electonics for Idiots"... .....

 

[GW208]

The 12V supply is now gone. No doubt my posts are confusing because I AM confused! If I could only find my copy of "Wiring and Electonics for Idiots"... .....

That's what were here for, don't give up yet. Look at your original drawing and just imagine the Led straight across the battery posts in that drawing. We know the light works then so all you need to do is trace your red wire back to the battery looking for a blown fuse or more likely a loose connection somewhere. I think you are getting close.

 

[PBJ2500CTD]

Gotcha.

A couple more questions.

Should I be concerned that the wires coming out of the LED being so small? Any danger there?

And, isn't this a resistor?

#ad


If it is, do I still need another one?

Thanks!

That would be the current limiting resistor that you see, so you shouldn't have to add one; and you need not worry about the wire being too small.

 

[BigPapa]

You cannot have two 12 volt devices in series on a 12 V circuit. Period

Anyone else have anything to add to this? Don't get me wrong Party. Just wanting a "2nd opinion". We're just talking about adding an LED indicator in the circuit.

 

[PBJ2500CTD]

Anyone else have anything to add to this? Don't get me wrong Party. Just wanting a "2nd opinion". We're just talking about adding an LED indicator in the circuit.

BigPapa,

To paraphrase what I believe Party33 is saying is that you cannot have 12 volts at both the input and the ground because there would be no difference in potential, therefore no current flow to energize the circuit. An example would be the top diagram in post #20. Electrons will take the path of least resistance, which would be the main circuit and not detour through higher resistance of the LED and associated resistor. The input and ground of the LED are connected to the same potential; ground in the case of the top diagram.

 

[BigPapa]

Ah, OK.



See, I don't even know what "series" and "parallel" is. If I could only find that book... ... .....

That would be the current limiting resistor that you see, so you shouldn't have to add one; and you need not worry about the wire being too small.

So, I don't need the resistor? Will adding another cause an issue?



Thanks!

 

[PBJ2500CTD]

Maybe cerberusiam can chime in here - what signal is on the OR/BK wire? Is this a ground for the TC? Is the circuit controlled via electronic switching, or through a relay in the "magic box"?

 

[PBJ2500CTD]

Ah, OK.

See, I don't even know what "series" and "parallel" is. If I could only find that book... ... .....



So, I don't need the resistor? Will adding another cause an issue?

Thanks!

Series means the circuits are inline, or tandem. Parallel is side by side.

 

[BigPapa]

Maybe cerberusiam can chime in here - what signal is on the OR/BK wire? Is this a ground for the TC? Is the circuit controlled via electronic switching, or through a relay in the "magic box"?

The Org/Blk wire coming from the PCM is the ground for the TC lock-up solenoid in the transmission. It is normally grounded by the PCM when conditions, vehicle speed, engine speed, throttle postion, and what gear the transmission is in, are right for the TC to lock up. Typically you just tap into the wire to ground it manually with a switch to force TC lock-up, but because my APPS is bad, causing the TC to lock and un-lock continually, I cut the wire and wired in a switch which means the TC will only lock up when I switch it.



This is fine for me driving but the wife drove it right after I put the floor switch in and accidently pushed the switch. When she had to stop for the car in front of her turning left the engine died and continued to die everytime she took off. She refuses to drive it anymore unless she can tell when it's locked.

 

[PBJ2500CTD]

The Org/Blk wire coming from the PCM is the ground for the TC lock-up solenoid in the transmission. It is normally grounded by the PCM when conditions, vehicle speed, engine speed, throttle postion, and what gear the transmission is in, are right for the TC to lock up. Typically you just tap into the wire to ground it manually with a switch to force TC lock-up, but because my APPS is bad, causing the TC to lock and un-lock continually, I cut the wire and wired in a switch which means the TC will only lock up when I switch it.

This is fine for me driving but the wife drove it right after I put the floor switch in and accidently pushed the switch. When she had to stop for the car in front of her turning left the engine died and continued to die everytime she took off. She refuses to drive it anymore unless she can tell when it's locked.

Your first diagram looks like it should work if a constant ground is sensed through the TC switch... at least in theory. Is that a hard ground in your circuit?