TC lock wire- Mine is grounded with key off!!!
 

This is a bit long winded. Thanks for reading!!
First the question......
On my '02 PSD, isn't the TCC wire (purple/yellow trace) supposed to ground out when the PCM sends the signal to lock the torque converter? More specificly it's the wire in the foreward GREY 16 pin connector on the driver's side wheel well that is widely used for the manual TCC lockup mod.

Now for the explanation of what I'm doing.
My torque converter fluctuates in & out of lockup cruising in O/D. So last night I went to install an LED indicator that will illuminate when the PCM sends the signal to lockup. Only the LED at this point, not a manual lockup switch, that will be next. This way I can monitor the tachometer fluctuating 300 RPM while watching the LED indicator to see if they are in sync. Anyway, I tapped into the purple/yellow wire at the fender well and ran it through the firewall into the negative of the LED. Then ran a power wire from the posative of the LED and attached it to a 12volt source that is always hot. Now the ignition was off, the keys were in my pocket LOL and the dam LED was on!!! I quickly disconnected the power wire to the LED and re-checked my wiring. Does this make sense to anyone? Shouldn't the led ONLY illuminate when the PCM locks my torque converter? I've read many write ups on this (including Guzzles) and they all say the same thing, the PCM sends the signal to lockup which grounds the purple/yellow wire.

Iv'e done a TON of troubleshooting with the tailights and trailer wiring and the brake switch (recall done) and ruled them all out as the cause of the torque converter locking issue. For now I need some advice to see if I goof'd up. Thanks FTE!!

I've never checked to see if the torque converter control solenoid control wire is grounded when the key is off. I never needed to know if it was, and I couldn't possibly care less if it was grounded when the key is off. What difference could it possibly make?

Change the power to the LED to a key on power and don't worry about what it does with the key off.

You also need a current limiting resister in series with your LED. If not you will dump a lot of current through the LED to the point where you can melt the wires.

I'm running a 10amp fuse between power and LED. The LED is a 15amp.

My point of concern is I wanted to run it by you guys to make sure I was tapping into the correct wire before I continue with the key on so I don't damage anything. It just did'nt seem right to me and I thought I had an issue. Sounds to me like it's not a big deal. Thanks guys.

A 15 amp LED? What are you using... a fog light?

:D

A fuse is not a bad idea, but even a 1A fuse is overkill for an LED. A fuse is not going to limit the current to the LED correctly. You want to put a 1k ohm resistor in series with the LED and the fuse if you want. A current limit resistor is way more important than the fuse in my opinion.

Yeah it lit up the cab like a spot light LoL. I bought a switch to do the TC lockup mod next week and it's a 15amp switch. the LED is a $3 12volt LED from radio shack.

Point taken. I'll pick up a 1K resistor tonight. Thanks for the advice.

Motorig, are you sure you want that much light in your cab when driving at night?

Do you mind posting the part number or a link of which Radio Shack LED you are running. 15 amps is a lot of light, heat, and current in a circuit spliced into your PCM and transmission. You might need a diode suppressor to keep from back feeding. LOL.

By comparison, the LED I set up for my TCC indicator is only rated for 15 MILLIAMPS, and it is plenty bright.

Ok it's not a 15 amp LED. I bought a 15amp switch for another project the same time I bought the LED and had 15amp was in my head when did the write up. The LED is in fact a 6mm LED w/red lense and a snap-in holder. Model # 276-084 bought from from Radioshack.
Here's a web link Red LED with Holder : LED Holders | RadioShack.com
The short amount of time it was illuminated last night I could see it was by no means bright but just enough to notice.

Now that makes more sense. As soon as you said "Radio Shack" I suspected you didn't have a 15 AMP LED after all, which is why I asked you for the part number. Your LED is only 15 mA, just like mine is.

You are correct about the wire color you chose Violet with Yellow strip, which is Circuit #480 that passes through Pin socket 4 of Connector C1048, that connects to Pin 54 of the PCM.

https://www.ford-trucks.com/forums/p...ctureid=151209

Awesome, thanks for the back up on this Y2K!!! So a 1K resistor is sufficient for the 15ma LED?

With 1k, it will draw 12mA. V=IR.

Sooooooo I have a funny story. I went to radio shack an hour ago to look for a resistor for my LED. As I was searching I came across an LED with a built in resistor for 4 bucks, SCORE!! I went ahead and bought a green and an orange colored, green for when the torque converter is in lockup & orange for when I've flipped the switch for manual lockup. So I'm all happy, I hop in my truck and drive away. Life is good...... LED's with built in resistors, ya! Then it happened.....I lost my torque converter. Yup, slip city. God played a mean joke on ME tonight. Luckily I was only a mile from my house. I babied it home it shifted fine other than the occasional shutter at 1-2 shift. I parked it and cried. That's my story, hope you enjoyed it.

BTW, thanks for the resistor info ebbnflow, I had forgotten about that formula.

Anytime. I'm glad you didn't melt any wired.

Sorry to read of your misfortune on your TC. It almost seems that the very failure you were trying to avoid happened anyway. I'm not quite clear on your meaning of "slip city", but I'm curious what happened.

Just to rule out all possibility for error, the first thing I would consider doing is to disconnect every bit of new wiring you added to the TCC circuit recently and restore it back to stock and retest.

The next thing I'd do is disconnect the oil to air cooler OUTLET from the cooling circuit and do a flow test into a bucket to see if flow is restricted through the cooler to less than 1 gallon per minute, to see if it got loaded up with clutch debris. I'd also draw a sample from the first pint that came out of the oil to air cooler and send it to oil analysis, if you do that sort of thing.

The next thing I'd do is drop the trans pan and look for clutch debris. I'd actually do this before the oil to air cooler test, but I still have several cases of cheap $1 per quart Chevron Mercon that I use as "utility" fluid for flushing that is only a $7.00 expense for a pan drop versus a $45.00 expense.

Just looking for evidence of clutch material.

Glad to learn you found the right LED's (with built in resistors). Green and orange were the colors I used (see my pic). Curious what RadioShack part numbers you ended up using. I forgot which ones I used... I had remembered the max current rating, but forgot the part number.

I also didn't remember having to solder in any resistors, so I refrained from comment when your question came up. Now that you said you found the LED's with the resistors built in, that was enough to remind me the reason why I did not have to do the math. I most likely bought the ones with the built in resistors.

My LED's have worked for 13 years now. Some people reported theirs failing after only a year or two, and finally giving up. I was even asked by a member what part number I used, since mine have lasted, but I couldn't remember, it had been so many years.

Hopefully, if you post the part number you used, then that member, and any future reader, will be reminded once more of which LED to get for this job.

Thanks for your condolences. I wasn't very descriptive earlier, I was just venting and trying to make myself laugh instead of throwing my lap top. What I meant by "slip city" was the transmission or TC was slipping badly.

I've had some time to collect my thoughts, I decided to test drive it again this evening while monitoring a few parameters on my Torque APP. I set it up to monitor TC slip, gear indicator & Transmission temp. The truck starts off smoothly in 1st gear with no issues. Once it shifts on it's own into 2nd it shutters and slips for a moment while losing acceleration then catches and starts to accelerate again. While in 2nd it will not slip at anything under 1/4 throttle. Any more throttle than 1/4 and it will slip about 300 RPM or so. Once it grabs it will shutter briefly as it stops slipping. The same thing occurs when downshifting from 3rd into 2nd. 2-3 shift is fine and does not slip at all even at 75% throttle (13 psi boost). And 3-4 shift seems fine as well with no slippage while in 4th gear (OD). Torque app shows around 900 rpm of torque converter slip while in 1st gear. When 1-2 shift occurs and the feeling of slipping happens, the 900 rpm TC slip stays at 900 until it catches again. The instant it catches, TC slip jumps from 900 to 1300 for an instant then back down to 900. That tells me the slippage I am feeling is in the transmission and not in the torque converter. I did this several times with the same results. Transmission temp never went above 150. Once I got home I checked temperature with an infa-red temp gun in multiple places on the tranny. The cooler supply line was 145*, return line from the cooler back into the tranny was 115* and the pan was 113*. No signs of overheating at all. The bypass line is colder than either of the tranny cooler lines. This tells me the bypass line is not hung open. If I'm wrong please correct me, I'm merely guessing off of what makes sence to me.
As for the oil analysis, that sounds like a great Idea. Also it sounds like you picked a good set of LED's since they've lasted you so long. Here's a link for the LED's with the built in resistor that I bought if anyone is interested.
Green LED with Holder : LED Holders | RadioShack.com

After doing a little research from what it sounds like so far is I've lost pressure to my second gear clutch. It could be as easy as a solenoid, but I won't get my hopes up. I forgot to mention that my OD light started flashing on my test drive last night. I have a buddy with the snap on scanner who can read my codes.

I don't see how it could be a solenoid. You need the code to begin the diagnosis.

The solenoid is a long shot. I poured in 2 bottles of lube guard into the transmission the day before this happened. My long shot idea is debris was freed up from the lube guard and is jamming the solenoid. I could be way off though, I don't even know if that is possible. I spoke to an engineer from Lubegard and that is his idea. He said it sound like 2nd gear clutch is losing pressure. I'm having the codes read this afternoon.

Ah HA... the truth leaks out of you little by little. Lube guard? What else did you do? First, you say your running a 15 amp KC Daylighter on your dashboard, and then come to find out you've got a normal 15 mA LED. Now the Lube Guard. What's next? :) (just trying to continue to support your humor coping mechanism)

You changed your LED choice to a better LED with a resistor, which turns out to be the EXACT same LED I bought 14 years ago, so you should be good for at least 14 years.

In case the Radio Shack link posted above breaks, let the forum record reflect that it is Radio Shack 276-271, a green 12 volt LED with a 16 volt peak voltage rating, a 15 mA current rating, a built in resistor, and only 24 millicandlepower brightness, which is only half as bright as the previously chosen red LED, at 50 mcd, which is too bright to be constantly on at night. This green LED is the one to get. Even the Radio Shack reviews reflect the positive feedback from other buyers using this LED for the same purpose. Finally, I can once again answer the question about what LED I used. Thanks for posting the link motorig.

Wishing you the best of luck with your diagnosis.

Uh-oh was I not supposed to use LubeGuard? Haha. If I wrote out everything I've done to this truck the "TRUTH" would be a 2 page reply.....geez LoL. Great info for the LED's Y2K, thanks for it. The wiring is still there but not connect at this point. I obviously have bigger issues now.

So about the recent issues. I found a shop on yelp with high reviews here in Orange County. They pulled the codes and test drove my truck all at no charge so that's good.
I don't have much time to elaborate, so my code is P0781 (1-2 shift). It slips now in first & 2. However the trans temp didn't go above 140° when I drove it to the shop and other than the slipping the transmission is functioning as it should. Meaning it doesn't shift erratically.

I'd like to call this thread complete. The TCC wire was the correct one purple & yellow. Thanks for the help Y2K and Mark Kovalsky.