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TC lockup switch questions.

Florin1
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Florin1

Florin1

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So I installed a tc lockup switch last night, and I'm not sure where I went wrong. I followed the tst website link but it doesn't seem to work. 

My truck junction box looks a little different than the one in his schematic but I'm pretty sure I did it right.

Here is what the truck is doing. First, with overdrive off, I'll get the truck to second gear, and flip the switch on, and nothing different happens. It'll shift up to next gear as I increase speed. Then I can come to a full stop and the truck doesn't want to stall or anything. Or I can be cruising at 35, and punch it and he truck will downshift. The only thing that seems to be different is if switch is off, and I get on the freeway and up to speed, and then flip it on, it seems to be locked. I can floor it and it won't downshift. But if I come to a stop like getting off the freeway, and I leave switch on, it still acts like switch is off. Like I can come to a full stop and it won't stall or anything. Then I can accelerate as normal. 

Was I supposed to ground out my switch to a ground wire or something? I found the orange and black wire at the ecm (my ecm connectors look slightly different as well. I have female end that plugs into male pins on the ecm) and followed it into the main harness along the firewall to the driver side where it comes out of the main harness. I tapped it there with one of those splitter snap connectors. Ran that through the firewall and to my switch and connected that end to the "on" terminal of my 2 post switch. The ground/off post I just grounded the to the metal structure behind instrument cluster. As for the junction box, I just pulled the trans relay, and jumped the two parallel posts, not the 3 post side. 

Where did I go wrong? Thanks 

Edited by Florin1
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jlbayes

jlbayes

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I bet you got the wrong wire. There are a couple orange with blacks in the harness bundle. ALL the pcm connectors are the same from 96-02. There are no differences I have ever found and poured over diagrams trying to find differences. I go right to the pcm C2 pin b11. Come away from the connector approx. 4"s and tap into the wire. Run wire into the cab to my switch and then from the switch to either the dash structure or column bolt. You will not have 2nd gear lockup with a stock vb. Even with the selector in D.

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Florin1

Florin1

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No I have not modified the VB. I'll poke the OR/Blk wire at the pcm and poke the switch wire to see if there's continuity. I guess that will tell me if I spliced into the right wire. 

How should I operate the switch once I figure out if it's working or not? On streets, OD off, wait till i get up to 35mph and then flip the switch? Or does the tc switch not have a purpose unless I'm on the freeway in OD? 

Also my ground is right no? I didn't have to ground into an actual ground wire. Body is fine?

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Tractorman

Tractorman

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2 hours ago, notlimah said:

What switch and location did you guys use?

 

I used to have a 99 Dodge with an automatic as well.  I used a momentary switch mounted on the floor near the park brake pedal.  The momentary switch was actually a universal horn switch (button).  It needed to have a low profile, be easy to depress (just the weight of your foot), and be robust.  The floor switch made it very easy and natural to control the lockup feature.

 

Whichever switch you use, you may find the converter lockup feature doesn't perform the way you might expect.  From what I recall, here is how I used my switch:

 

I put the gear selector in "Drive" and turned the "Overdrive" switch off and started driving the truck.  When the transmission shifted into third gear, I watched the tach for a small RPM drop noting that the PCM had just locked up the converter.  When converter lockup occurred, I immediately pressed and held the floor switch as I modestly accelerated the truck in lockup mode.  As the transmission approached the shift point for fourth gear, I easeup on the throttle and released the foot switch momentarily to allow for the shift and for the PCM to command lockup in fourth gear.  When that occurred I immediately pressed and held the foot switch. 

 

Under normal driving at highway speed the PCM will keep the converter locked up, so you can release the foot switch and drive the truck.  If you need to slow significantly for a curve, but don't want the converter to unlock or the transmission to downshift, then you press and hold the foot switch (before PCM has a chance to unlock the converter) and drive through the curve in a normal  manner.  Once you have manually locked the converter in fourth gear with the foot switch, it will remaine locked in fourth gear whether accelerating, coasting, or braking until you release the foot switch.  This feature is useful to help slow the vehicle when traveling down grades as well.

 

Reverse the procedure when shifting from fourth to third with a touch of throttle during the downshift.  After a little practice you will see that it works quite smoothly.  By using this procedure you will never have the converter locked during a shift, and  it makes for smooth and precise shifting even pulling heavy loads.

 

When I had my 99 with an auto, I had an exhaust brake controlled through the same foot switch as well - a great combination!

 

Attached is a schematic confirming what Jlbayes posted.

 

- John

Lockup Wiring.JPG

Edited by Tractorman
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IBMobile

IBMobile

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Here's how I installed my switch. Using the momentary switch the torque convertor will lock up in third and will up shift to 4th but will not down shift from 4th to 3ed.  By using the two relays the torque convertor will stay locked and with the tap of the brake peddle or pushing the momentary switch will unlock.  I have added a head light floor dimmer switch so that it will stay locked up on long down grades while using the breaks.

I'm putting together another kit to install and will probably do a wright-up on it then. 

 

https://mopar1973man.com/topic/9956-mystery-switch-sets-p0122/ 

 

 

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notlimah

notlimah

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1 hour ago, Me78569 said:

 

 

Yea I've read your write up a few times Nick, not entirely sure if I want to attempt the same. If I were I think I'd want a toggle switch though.

 

@Tractorman I think that's an awesome idea!! I hope you don't mind if I steal that foot switch location?! Do you think a toggle switch wired to a small LED would work the same way? I think it'd be even more convenient to be able to just tap it with your foot once and it either be on or off. But I get that forgetting to unlock will cause issues, that's why I think an LED to signal it's on would solve that problem. 

 

22 minutes ago, IBMobile said:

Here's how I installed my switch. Using the momentary switch the torque convertor will lock up in third and will up shift to 4th but will not down shift from 4th to 3ed.  By using the two relays the torque convertor will stay locked and with the tap of the brake peddle or pushing the momentary switch will unlock.  I have added a head light floor dimmer switch so that it will stay locked up on long down grades while using the breaks.

I'm putting together another kit to install and will probably do a wright-up on it then. 

 

https://mopar1973man.com/topic/9956-mystery-switch-sets-p0122/ 

 

 

 

Look forward to that write up! After I let dynamic get my trans tuned I should have 3-4 locked up shifts and 4-3 locked downshifts so that should be nice. I do believe he said a stock valve body could lock in 2nd, maybe I misunderstood.

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Tractorman

Tractorman

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16 hours ago, notlimah said:

Do you think a toggle switch wired to a small LED would work the same way?

 

 

 

I tried different setups and I found that a momentary, easy to actuate ,low profile sturdy switch worked the best.  It took me awhile to find my final switch, but I did find one on Amazon.  The switch is contained in a metal frame that is less than an inch tall and has a large operating platform that has a mechanical stop so the switch inside will not be damaged.  I have the switch held down by two carpet tacks and Velcro backing so the switch won't move around.  This mounting method also allows for the switch to be placed anywhere and for easy removal when cleaning the floor.

 

You could wire the switch in parallel with an LED light and have a nice setup.  If you are considering this approach, just search on-line for "foot switch on Amazon" and you should be able find one right for your budget.

 

- John

Foot Switch (metal).JPG

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Tractorman

Tractorman

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1 hour ago, notlimah said:

Thanks @Tractorman do you happen to have a link for the one you used?

 

Unfortunately, the my particular switch is no longer available.  It was made in China and cost less than $5.00 at the time, including shipping.   I think it was made by 8 - 10 year old kids because it was of good quality.

 

II think if you keep searching on Amazon you will come across something that will work.  A Linemaster T-91-S Treadlite II looks like it would work (1" tall).  It sells for around $20.00.  It looks like you can get it with or without a cord.  Either way you will have to do some modification.

 

- John

Foot Switch (Linemaster).JPG

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