Manually sending 12v to an ECU output line = issues?

[-Nemesis-]

Just wondering what if any implications there would be to this?

I'm talking about a torque converter lock up circuit, one wire from the ECU to the solenoid. When the ECU sends 12v the lock up does it's bit.

For the sake of using what I already have in the shed (a nice LED rocker ON/OFF switch) and simplicity of the circuit. I'm wondering what faults if any would occure from splicing my manual 12v signal into the existing circuit. So, when the switch is activated the whoe line will see 12v and the converter will lock, but this will also mean the output pin on the ECU will see 12v. Is this likely to harm something, or make the ECU see some random error and play silly buggers?

I'm talking about a lock up switch for a 1FZ 105 series Auto.


If it will cause drama's i'll buy some stuff for a proper change over circuit.

[DamTriton]

...........Diode
ECU---------|>------@--------------------To lock up converter
From switch-------/

You need to insert a diode between the ECU and the switch output to the LUC (ignore the full stops and try to make sense of the diagram above)

If you can let me know what current the LUC needs I can suggest a diode. If the current is above about 5 amps or so you may need to switch through a relay rather than using the switch to do the work.

[-Nemesis-]

Ok thanks, sounds simple enough will have to dig out the multi.


I'm having a mental block day! Trying to get my head around using a relay (change-over?) to wire so I have one output wire, with 2 different signals I want to switch between. Powered from some sort of switch on the dash (on off.) Can you make me slap my forehead and suggest a way? I'm sure it's simple, but keep going round in circles (at work talking to bloody truck drivers at the same time lol)

Cheers

[DamTriton]

It depends on EXACTLY what you want to do.

If you are only looking at being able to switch the LUC on when you want then the above diagram is what you want.

If you want to switch it OFF manually then you will need a modification of the above cct with a relay added. I cannot see any reason for wanting to disable the LUC at any time if it wants to engage (can usually be done manually by dropping out of overdrive gear manually anyway). Doing so will only increase your ATF temperatures

[-Nemesis-]

What I'm after is a constant LUC signal the entire time as per factory, except for when I want to manually lock it with the 12v signal. So in effect 'OFF' is the original output signal from the ECU.

In my last post by an on/off switch I was just meaning the utilising of a rocker switch in cab. I'm also going to get the 12v signal to power a little led on the dash to remind me it's manually locked.

[DamTriton]

All you need is the Diag I posted.

This gives a choice of "Normal" and "ON"

Red LED with about 470 ohm resistor across the LUC will light up when it is active (switched or normal)

You would need to put another diode in cct between the junction and switch and take the LED from the switch output to only show when you have it manually switched on

ie

ECU-------------|>-------\_________ to LUC
Switch---|-----|>-------/
..To LED |

[-Nemesis-]

Awesome, too easy thanks mate.

[-Nemesis-]

FYI this is the picture of a kit from the seller I originally looked at, but they want $200 for it!

[DamTriton]

FYI this is the picture of a kit from the seller I originally looked at, but they want $200 for it!

I'm seeing about $20 tops..........

Looks like it only uses a single pole dual throw (SPDT) relay to switch between "ON" and "Normal".

Failure of the relay = Failure of the LUC = Possible overheating of transmission.

Prefer the diode method - less likely to fail if appropriately sized diodes used. The override function would use a relay to switch current, basically a redundant thing if it fails.

I also see a 10 amp fuse meaning current is not too severe.

The two diodes could be from a bridge rectifier - cost ~$5 from most electronics outlets (DSE/Jaycar/Altronics). Use the ~ inputs for the ECU and switched power and the +ve terminal for output to the LUC. Cut off the -ve terminal as it will not be used.
http://www.altronics.com.au/index.asp?a ... m&id=Z0089" onclick="window.open(this.href);return false;

[-Nemesis-]

A quick Narva Rocker switch Q for ya's, as I haven't seen it before. I've got one of these






What is the Relay Switch (Opt) terminal? My first thought was it's a secondary power out, but the test light shows nothing when the switch is activated, while Acc gets 12v as expected. Mind you, the LED doesn't work properly (flicks on for a millisecond then goes off) so the switch could be faulty more than just the led....

[DamTriton]

A quick Narva Rocker switch Q for ya's, as I haven't seen it before. I've got one of these






What is the Relay Switch (Opt) terminal? My first thought was it's a secondary power out, but the test light shows nothing when the switch is activated, while Acc gets 12v as expected. Mind you, the LED doesn't work properly (flicks on for a millisecond then goes off) so the switch could be faulty more than just the led....

I would assume the (opt) means it is optional mad may not have a connection internally. Have you checked it against all terminals in both switch positions?

Power to the Gnd and Power will be needed to turn the LED on.

[-Nemesis-]

Power to the ground side?

ATM I have switch (tested it with a break in the LUC line, results are awesome drive wise) with Power getting 12v from Ign, Ground is Earthed, Acc is Solenoid. When I first wired switch up with just pwr and earth, I'm sure the LED was working. After I slotted the switch into the hole, I noticed the LED flickers as you press it (sometimes) for a millisecond and then nothing. However, the Acc is powering as per normal etc....


Also, finally got an amps reading, though I only have my old $10 multi so not sure on accuracy. Was seeing 0.89-0.90 on the 10 A DC port, sound about right?

[DamTriton]

Sorry, I meant "power" as a general term... +12v to the Power terminal, and earth/0v to the ground terminal, with your LUC to the Acc.

The ground terminal needs to be earthed to allow the LED to work (may explain the flicker as you switch it on).

That sort of current (<1amp) would be OK through the switch alone, not much more that a relay.

Your circuit with connectors etc could end up being done for less that $10.

[-Nemesis-]

Ooops shoulda mentioned the <1amp is the signal from the ECU, in regards to a diode. Or do I need to measure the amps from my switch supply to pick the diode? Didn't think of that...


(thanks for the ongoing help)

[DamTriton]

ECU----------------LUC
^^^ <1amp? ^^^

Is that what you're saying? You will need a blocking diode for safety (don't know the internal circuitry of the ECU) and also a blocking diode in the switched 12 v line to allow the LED in the switch to be on only when the switch is on (without the blocking diode the led will be on whenever the LUC is locked regardless of switch position).



http://www.jaycar.com.au/productView.as ... BCATID=379" onclick="window.open(this.href);return false; Would be good.
http://www.jaycar.com.au/images_uploaded/BR605610.PDF" onclick="window.open(this.href);return false; Data sheet for it showing pinout

ECU to one ~ terminal (AC in)
Switched 12v to the other ~ terminal (AC in)

+ terminal goes to LUC (Top incorrectly labeled "DC in" wire in diagram - should be DC out)
Snip off negative terminal (Bottom "DC in" wire, not used)

Feel free to make a bunch of these and flog them for $200 each as a "Solid State equivalent - no more relays blowing up!!!"

Price of switch $15, Price of rectifier $2.50, Price of wire $0.20, Price of connectors $0.50.
Knowledge to put it together, priceless

[-Nemesis-]

Hahah legend thanks mate, did all the hard work for me! Just gotta find time to dare drive into Penrith to Jaycar in amongst this xmas chaos.


I rechecked that switch earth too, moved it to another part of the body (uncoated metal bracket bolted to the body) and same thing, no LED. Hmmm...... I've wired up 100 LED switches before, guess this may just be a dud somehow, it's not even flickering now.

[-Nemesis-]

Went and bought the rectifier today, had to get the next size up because coincidentally (or someone sniped your idea lol off here) someone had been in the day before and bought their entire stock of bridge rectifiers in your link from Penrith Jaycar


I also thought to by a push style momentary on/off switch. I'm going to plumb this between the hard rocker switch and the LUC (bridge). I'm mounting it on the inner edge of the left foot rest. So if I need to momentarily disengage the LUC i can simply use it like a clutch. Not that i'm going to drive it like a manual. Mainly for off road etc so the vehicle doesn't stall if I cant get to the rocker.