View Full Version : Hot Wiring the Overdrive

03-07-2003, 12:47 PM
As you know my TPS is shot and my O/D has never worked since I got the truck. I was told the solenoid was unplugged inside the tranny. Well it is plugged in, but the TPS is shot. So my question is. What 2 wires are the ones that control the O/D on the transmission. I found a plug on the drivers side top of the trans that is vertical straight up and down. It has a small ornage wire and a larger blue wire. I tapped into the blue wire and when I hooked it directly to the battery for a test everything on the dash came on. All the gauge lights, the intake heater cycled, and the WTS lights came on. So then I tired the orange wire and test drove it and nothing changed. Did I find the right wire, or is the solenoid really bad? Can someone shed some light onto if I have found the right plug or the right wires. Thanks, Bill

03-07-2003, 04:46 PM
The blue wire is ignition feed, the reason everything lit up when you hooked to the battery is because you backfed the accessories.<br>For normal OD operation, power is fed to the blue wire through the ignition switch and the orange wire (with a light green tracer) is grounded by the engine controller.<br>For manual operation, cut the orange wire near the transmission and hook the wire to a dash mounted toggle switch that routes the wire to ground. Once the transmission shifts to 3rd gear, flipping the switch should engage the OD.

03-07-2003, 07:21 PM
Thanks, I am going to try that first thing tomorrow. I got that same answer on the, well another board. :o Thanks again, Bill

03-07-2003, 11:14 PM
I couldn't wait till the morning. ;D So I went out in the barn tonight and hooked everything up. Low and behold the SOB works. :o :o ;D First time since I have owned the truck I have had O/D. I just had to drive 10 miles out my way and go get on the Interstate. I hit 85 before I got out of it. 8) Mani it is nice to be able to pass somebody for a change. :o I am so happy now you don't even understand. Thanks, Bill

11-04-2003, 12:49 PM
Can the overdrive by engaged in second gear or is there something in the transmission that will only allow overdrive after the transmission is in third gear?


The Old Man
11-04-2003, 09:28 PM
Dang that sounds interesting. My OD has always worked but it&#039;s sort of a PITA to remember to turn it off everytime I start the engine. Usually manage to hit the cargo lite by mistake. ::) Let us know how you like that toggle switch after you&#039;ve played for a while.


11-04-2003, 10:25 PM
Mine has been wired through a toggle switch now since March, I love it. I can turn it on when I want it on and off when I want it off.


11-05-2003, 12:47 AM
Darn it Pat, I told you that SamsRams has a nice install that uses a second gen shifter column with the OD button on the end. ;) :D It is a great little addition for us auto guys....
OH, using OD down low, in and around the torque band is pretty much an ugly propsition unless you&#039;re trying to kill OD so you can get a decent fluid coupling system like Bill&#039;s...
Remember the comments on how the 727 is a good transmission and the A518 is a 727 with an OD bolted on...... and.... the OD is the weak link.... yada yada yada.... well...

Pastor bob.

The Old Man
11-05-2003, 07:19 AM
Pastor Bob, ya caught me. 8) You told me so darned much the th&#039; old brain didn&#039;t have room to store it all. [laugh] Where do I go for that shifter column? Yeah, I&#039;m one of those who likes to use the OD only on the highway and then will turn it off on long pulls uphill. Have a good day.

11-05-2003, 09:25 AM
Get it at your local D/C dealer. It is the shift lever for the 2nd gen trucks. Got mine a month ago and it was $49. Less than an hour to hook up.


11-06-2003, 08:15 PM
I ran the wire from the tranny to a terminal on a new floor mounted headlight dimmer switch (went to parts store and asked for any generic one they had). From that same terminal I ran a wire to an aftermarket dash light - the other portion of the dash light was wired to a hot ignition fuse.
The other terminal of the dimmer switch went to a ground.
Use a &#039;scotchlock&#039; connector so you don&#039;t have to cut the orange wire - just splice into it.
My truck had intermittent problems - now when the truck hits OD on its own the light comes on. If the OD acts up I use the dimmer switch to activate it and the dash light lets me know if I left it on by mistake.

Just a cheaper, yet reliable, solution that I used.