Brian P Posted May 27, 2008 Report Share Posted May 27, 2008 I thought the PWM wire was black but it's been a while. This image: http://60degreev6.com/Articles/Transmissions/4T60E/4t60e_wiring.gif Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 27, 2008 Author Report Share Posted May 27, 2008 Then cut the wire from the PWM solenoid, and then to actuate the normal TCC solenoid, just ground out the tan w/black stripe wire on Pin D of the trans connector... That will close the circuit and actuate the solenoid... To eliminate the PWM solenoid, just cut the brown wire on Pin C of the trans connector and seal the end or crimp on a butt connector... I'm starting to get this...slowly. What is the PWM solenoid, and what does it do? Better yet, what does PWM stand for anyway? Also, I'd really love it if you could explain what I need to do based on that diagram. I'm still a bit confused on what I have to cut/splice/close off just based on the way you worded things. So far here's what I'm getting. 1. Cut Brown wire on Pin C and crimp with butt connector 2. Splice tan/black stripe wire on Pin D and ground that splice using the switch. Am I getting this correctly? Edit: I tried the following listed above, and I noticed that with the switch in the On position, the TCC wouldn't lock up, and with the switch on the off position, the TCC would lock up rather briskly. However, it would only lock up if it was in the RPM range that it used to lock up in, so I couldn't theoretically force it to lock up whenever I wanted to. In addition, it would get out of lockup if I hit the throttle above a certain position, exactly the way it did before. The only difference is that now, it seemed that it would stay in TCC longer upon harder acceleration than before, but this doesn't really do me much good because the moment I let off the gas, it goes out of lockup. If there's really no way to do what I want to do without going insane, I'll just butt crimp all the wires back together the way they were from factory and call it a day, but I'd prefer to get this working if I can. Quote Link to comment Share on other sites More sharing options...
Brian P Posted May 27, 2008 Report Share Posted May 27, 2008 If you scroll up I already explained the function of the PWM solenoid, and it stands for "Pulse Width Modulated". I don't know why the method above didn't work as that's exactly what I did, and it worked fine for me. How does your switch in the "off" position let the TCC apply? Maybe your PCM gives a positive signal instead of grounding the circuit, and when you flip the manual switch on, the voltage goes straight to ground instead of thru the solenoid. That is very possible. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 27, 2008 Author Report Share Posted May 27, 2008 If you scroll up I already explained the function of the PWM solenoid, and it stands for "Pulse Width Modulated". I don't know why the method above didn't work as that's exactly what I did, and it worked fine for me. How does your switch in the "off" position let the TCC apply? Maybe your PCM gives a positive signal instead of grounding the circuit, and when you flip the manual switch on, the voltage goes straight to ground instead of thru the solenoid. That is very possible. Well I know for a fact there's a positive current coming out of the tan wire from the transmission. Don't know if that helps understand anything though. The switch I have just connects that current to the ground, so it seems pretty much exactly what you're referring to. Any way to get around this? Quote Link to comment Share on other sites More sharing options...
Brian P Posted May 27, 2008 Report Share Posted May 27, 2008 Actually that's not quite what I was trying to describe. In my car, the solenoids all get power from one source, Pin E and it's spliced going to all solenoids internally in the trans. The PCM then sends a switched ground to whatever solenoid it wants to control at A,B,C,D. Basically just like how that diagram shows. When you found power at the tan wire, was it connected to the trans? Do you happen to know the model code of your trans? Maybe try probing the connector with Key on/ engine off and see which wires are showing voltage just to be sure. I would hate to think GM used different wiring assignments depending on powertrain, but I've seen crazier things by the General. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 27, 2008 Author Report Share Posted May 27, 2008 Actually that's not quite what I was trying to describe. In my car, the solenoids all get power from one source, Pin E and it's spliced going to all solenoids internally in the trans. The PCM then sends a switched ground to whatever solenoid it wants to control at A,B,C,D. Basically just like how that diagram shows. When you found power at the tan wire, was it connected to the trans? Do you happen to know the model code of your trans? Maybe try probing the connector with Key on/ engine off and see which wires are showing voltage just to be sure. I would hate to think GM used different wiring assignments depending on powertrain, but I've seen crazier things by the General. I found power at the tan wire connected to the trans after I had cut it. I don't know the model code. I'll see if I can find something when I probe the connector if I can get to it tonight. Any other ideas? Quote Link to comment Share on other sites More sharing options...
Brian P Posted May 27, 2008 Report Share Posted May 27, 2008 You should show power at the Tan wire if the plug is connected to the tranny. When disconnected, the only power source should be coming from Pin E, others should be dead or maybe grounded at most (I'm ignoring the temp sensor wires). The power comes in thru pin E, then goes thru each solenoid where it will complete the circuit when grounded by the PCM. So assuming the PWM solenoid is disconnected, grounding that tan wire thru a switched source should trip the TCC. Do you think the indicator lights are causing an issue? Maybe try a very simple switched circuit by adding a wire from the cut tan wire (tranny side) to a ground source inside the car, with an unlit toggle switch between it. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 27, 2008 Author Report Share Posted May 27, 2008 You should show power at the Tan wire if the plug is connected to the tranny. When disconnected, the only power source should be coming from Pin E, others should be dead or maybe grounded at most (I'm ignoring the temp sensor wires). The power comes in thru pin E, then goes thru each solenoid where it will complete the circuit when grounded by the PCM. So assuming the PWM solenoid is disconnected, grounding that tan wire thru a switched source should trip the TCC. Do you think the indicator lights are causing an issue? Maybe try a very simple switched circuit by adding a wire from the cut tan wire (tranny side) to a ground source inside the car, with an unlit toggle switch between it. Wait...I butt connected the tan wire back together, lol. Was I not supposed to? Do I ground switch the tan wire on the transmission end or the other end? Quote Link to comment Share on other sites More sharing options...
Brian P Posted May 28, 2008 Report Share Posted May 28, 2008 You need to ground the tranny side of the wire. I had just spliced the wire and it worked for me, but if you cut the wire, you'll be protecting the PCM from this experiment. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 28, 2008 Author Report Share Posted May 28, 2008 You need to ground the tranny side of the wire. I had just spliced the wire and it worked for me, but if you cut the wire, you'll be protecting the PCM from this experiment. Alright, I'll give this a shot when I get home tonight. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 29, 2008 Author Report Share Posted May 29, 2008 You need to ground the tranny side of the wire. I had just spliced the wire and it worked for me, but if you cut the wire, you'll be protecting the PCM from this experiment. Alright, I'll give this a shot when I get home tonight. Well I gave it a shot. I spliced the transmission end and the PCM end of the wire and tried to switch it on, and absolutely nothing changed. The car still wouldn't engage the TCC. With the brown wire at pin C cut and the tan wire connected back to the transmission, the transmission would go into TCC, but rather firmly; a little too firm. When engaged during 3rd gear and shifting up into 4th gear, the shift would also be very firm. On the bright side, with this arrangement, the TCC stays engaged longer with more throttle before disengaging. However, the moment you let off the gas, it disengages as would be expected. Any further ideas? When I disconnect the plug, the only current coming from the PCM side is at pin E, and there is no current coming from any of the transmission plugs. I wonder what would happen if I switched the wire at pin E as a connected/disconnected switch. Quote Link to comment Share on other sites More sharing options...
Brian P Posted May 29, 2008 Report Share Posted May 29, 2008 well pin-E supplies power to all the solenoids, so I wouldn't go doing that So you didn't cut Pin-D (tan), but spliced it, and it didn't work? I wish I still worked at my old job (service department) I could get any wiring diagram I want. Something's gotta be different here. Actually maybe my '95 GM service manual covers the entire w-body line.... Quote Link to comment Share on other sites More sharing options...
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