Functioning Cruise Control after an Auto to Manual swap on a 2G

[da_reeseboy]

I wanted to post this tutorial in the tech articles, but I'm not sure if it should be in drivetrain tech with the tranny swap manuals, or in the electrical section. I also wanted to get some feedback on it before posting it in a tech article. With that said, check it out and let me know what you think.

Tutorial -
When you swapped the trannys you had to bypass the park/neutral switch so the car would start. This simply tells the ecu that the car isn’t in gear so its safe to start. Of course, that also says its unsafe to engage the cruise.

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*** If you still have the TCU/TCM, remove it. Its not needed and will give you a CEL once you fix the cruise. ***
There are 3 methods to re-enable the cruise –

1. Instead of shorting the 2 wires together, run them to the switch on the top of the clutch.

2. If you don’t want to run wires thru the firewall, then you can run them from the starter relay, which is located under/behind the radio in the dash.

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It was the relay on the left in my car but my Chilton’s manual shows it on the right, so go by the wire colors to be sure. It’ll have a thicker black w/yellow wire, 2 thicker black w/red wires, and a thinner black w/red wire.

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Cut that thinner black w/red wire and extend both sides over to the switch on top of the clutch.

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3. If you are like me, you want the cruise to work but you don’t want to push the clutch in to start the car. So I ended up having to wire in 2 relays – 1 that bypasses the clutch when you turn the key to the start position, and a second that completely disables that first relay if you enable the cruise control. It sounds kind of redundant but it’s the only way I could get it to work. I’ll explain why after I tell you how to do it for the sake of those who just want to know how to do it.

You’ll need 2 SPDT (single pole double throw) automotive relays like this -

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you can find them at an electronics store, on e bay, AllElectronics.com, or just about anywhere else on the web.

Start out by cutting the thin black w/red wire going to the starter relay and extending both ends to the switch on the top of the clutch like method 2.
Next tap into the 2 wires that you just ran over to the clutch switch (don’t cut, just tap into them) and run those splices to relay 1 pins 30 and 87. Now tap into the thick black w/red wire marked below -

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and run that to relay 1 pin 85.
Now run a wire from relay 1 pin 86 to relay 2 pin 30. Run relay 2 pins 86 and 87a to a ground.
Finally, run relay 2 pin 85 over to the back of the cruise control switch located on the left of the gauge cluster (it just pops out with a flat head screwdriver) and tap it into the blue w/black wire shown below -

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Done! Put it all back together.

For those that care to know, here's why we had to use 2 relays - the ecu seems to monitor the wire we tap for enabling relay 1 and so if the circuit is complete (pin 86 grounded out) then it will not allow the cruise to be engaged. It wasn’t enough power to enable the relay (only about 0.6 volts) so it wasn’t until I hooked up a multimeter that I finally figured out why it wasn’t working with just the one relay.
If you know of a place to tap that has power only when the ignition is turned to "Start" let me know so I can try it and revise this tutorial.

 

[da_reeseboy]

Getting a CEL code from method 3. I didn't notice it yesterday because I have a JDM motor (no egr) so my CEL is always on. I just checked the codes like I habitually do to make sure its the same as always and noticed a new code - P1750 . I'm pretty sure I know what it is - I just need to change what relay 2 is controlled by so it disconnects relay 1's ground immediately after the car is started... maybe I'll just have it trigger off the radio power instead of having to run it all the way over to the cruise switch - it would definitely be easier to get to since your behind the radio already. I'll update when I get it fixed.

Update - Did some searching around here and found out the code is pointing to A/T solenoid malfunctions. That makes sense that its reading malfunctions since they don't exist. I'm gonna snoop around some more and see if I can find a solution for this.

Update 2 - The code is indeed from the TCU/TCM. If you still have the TCM/TCU get rid of it - you don't need it. I also updated the tutorial to reflect that info.