Converter Switch Mod question

[Highridge]

So my truck for a while now has had a problem with the torque converter randomly locking and unlocking while on the highway and it was driving me up the wall. I cleaned and greased every switch and sensor I could find and traced every wire. So rather than let my converter destroy itself I decided to put in the lockup switch and just keep it off for now. It works great for controlling lockup but my question is what to do about the flashing O/D light that happens because of it. I see that some guys have put in a resistor to trick the computer into thinking the converter is locked. My question is what size and how to connect it? Right now from what I've read it seems that a 10k ohm, 10 watt resistor that grounds the lockup circut will work and keep the pcm from going into limp mode. Does any of this sound right?

Thanks
Derek

 

[LCAM-01XA]

You need a 20-22k resistor, the small kind (not power resistor) seems to work just fine for me. How to wire it up, well the idea is to feed the dummy signal to the PCM at the same time as grounding the TC, here's a little something I came up that will allow you to do just that:

The different current paths are showed in different colors: red is auto control, green is manual locked, and blue is manual unlocked (comes handy sometimes). You will need an On-Off-On DPDT switch and a 5-pole Bosch-style relay.

 

[Highridge]

Ok so I bought a 22k resistor that is 1/2 watt. Will that work? So one end goes to the pcm and the other gets key-on power, correct?

Thanks
Derek

 

[LCAM-01XA]

Yes, and yes. Th reason for the resistor is that it causes the same voltage drop as the converter lockup solenoid inside the trans, so for all intents and purposes the PCM can't tell the two apart - who and how figured out the resistance value I have no idea, all I know is that it works just fine on my truck

 

[Highridge]

Ok so I installed the resistor and went for a drive and it promptly went into limp mode just like when I didnt have the resistor. Codes say converter clutch failure (obv) and shift solenoid 1 failure? maybe this is a different issue alltogether.

 

[Conky]

Mine was doing that at around 50 miles per hour
If I went faster it would lock and stay but at 50 mph or less it would in and out all he time
I put a converter switch into my 90 f-250 2 weeks ago
it works great, all I did was cut a switch into the purple/white stripe to disable the lockup, kinda like a city/ highway switch

I dont have any flashing od light or any other probs it works great
very simple mod. I cut the wire several inches above the tranny connector and then up the firewall and into the cab andmounted it next to the od switch

 

[LCAM-01XA]

Highridge, the Shift Solenoid 1 is independent of the converter lockup solenoid, SS1 is responsible for the 1st and 2nd gear application (energizes for 1st, shuts off for 2nd) - does your truck start off in 2nd gear always?

And I have no clue why the resistor don't work for you, I have mine feeding the PCM constantly and my converter is on full-manual on/off control and all works perfect...