can i delete overdrive completely or reverse the switch to turn it ON instead of OFF.

2002 3.0 AUTOMATIC

the employees aren't turning it off when towing. one tranny is about gone, i'd like to save the others.

 

Might need a program for that, Wayne. I believe the default in the PCM is to come up with it on everytime.

You could make a circuit to deliver a pulse to turn it off several seconds after the truck starts probably. That's the only way I can figure to make it work unless you can "tune" the setting.

 

i know with mustangs they can disable the traction control button. thats what got me thinking about it.

 

Hey, did you get to play with the controller I sent you yet?

 

no. not until my cast comes off. one handed.

 

Dang, I completely forgot about that!!! Hope you're healing up well and don't have much pain.

 

John is right (of course!). The O/D is reenabled at each key-up regardless of the mode when the key was turned off. It requires an input from the TCS after every start to cancel it.

One way to get around this might be to take a hint from how the auto door locks work on Explorers and others. They use a hit from the reverse light wire to tell a module that the driver has taken the vehicle out of Park. Since this happens after every start in Park before the vehicle can move, it might also provide the basis for an "auto-cancel" circuit for the overdrive.

 

The only problem I see is that it would toggle between O/D ON and O/D OFF every time it went into reverse after the start. So, there could be situations where it would possibly end up in O/D ON after some foward/reverse maneuvering. So you might need something like a latching circuit to keep it in O/D OFF.

 

That's a really good idea, Bob -- I didn't think of something like that.

You could condition it with a gate circuit with one input from the reverse, and one from the overdrive off indicator bulb. The circuit could be set up to function only when the OD bulb was off.

Trying to think of the simplest circuit to accomplish this with simple relay and/or diode logic. If I come up with something, I'll post it.

 

I can do it with one resistor, one diode, and $1 to $2 opto isolator. But you have to breadboard a small circuit board to do it. I'll draw it up later and post it.

 

Here it is. It assumes a few things I cannot verify from here right now:

1. The OD cancel switch wire gets taken to ground to toggle the OD function.

2. The OD light is fed with a more-or-less 12 volt signal to illuminate the lamp. Anything over about 10 volts would be fine.

3. The OD switch switches a couple of hundred milliamps or less.

4. The OD light is illuminated by applying power to the lamp when needed -- not by leaving it with power on one side and grounding the other side to light it up.

If those conditions are met, this should work.

Edit: I guess I should explain it.

The opto isolator is a "relay" like device that turns a transistor switch "on" when the led is turned on.

So, the OD lamp forms a virtual "ground" for the LED when it is not lit up. Diode D1 prevents "back feed" that could damage the LED when it is lit up.

The resistor limits the current from the reverse lamps line.

If the overdrive cancel is off (OD light not lit), then when the reverse lights are powered, the LED in the optoisolator gets current through R1, then down through D1 to ground.

This turns on the transistor in the output, which grounds the OD cancel switch line.

This lasts until the OD cancel light comes on, then the LED no longer has current flowing through it, and the opto transistor turns off again.

It's elegant because it provides a pulse which lasts until the PCM responds by turning on the OD cancel light.

 

1. The TCS (cancel switch) does not go to ground. It is wired directly to switched B+ on one side so it can't. The PCM supplies ground through a resistance.

2. Switched B+ when the running lights are off but through the dimming module when they are on.

3. Probably true.

4. The bulb is powered from B+ in start/run or from the dimming module when when the exterior lights are on; ground is supplied by the PCM when appropriate.

 

Hmmm...I'll have to come up with a "plan B", lol...

Thanks. That'll help me nail it down. You've got to admit it was a simple and elegant solution though -- albeit one that WON'T WORK!!!

 

Wow. Never looked at it before, but these two do surprise me. I wouldn't have thought any indicators were powered by the dimmer as you might inadvertently dim them out completely.

 

lol this thread is like the freaking brain trust with all this mumbojumbo

 

We're card-carrying, senior members of the "Freaking Brain Trust"...oh wait, my card says "Freaky Brain Trust", sorry...

 

I wish I knew some of this stuff