jdperk-86elco

I have installed the Corvette drive-by-wire system to get cruise control but for some reason I can not get the cruise to work. The throttle works fine and the car is driveable.

I have had a friend use a scanner to monitor the stalk switch and brake switch while driving and he stated all the signals are there.

Questions:

Can the cruise function can be turned off in the PCM?

Can EFI Live view the switch inputs for troubleshooting and can it turn on the cruise functionality? I am going to purchase EFI Live soon.

My wiring looks correct and I tried a new TAC box so my last thought is that the cruise is turned off in the PCM. The brake switches look to be correct.

Thanks for your help

Stu Cool

iTrader: (13)

I am about do go down this same path, just got my switch. I will be very interested in any replies you get.

Pat

jdperk-86elco

Pat,

Thanks for the reply at least I know someone is interested in my issue. This is I think the best setup since it doesn't mess with throttle cables and one gets instant cruise by hooking up the cruise stalk switch. This was very simple to install. This should have worked just by hooking up the wires but somewhere I have an issue that I haven't solved yet.

I got my setup from SpearTech and John has answered all my questions and even sent me a TAC (Trottle Actuator Control) box to help me diagnose my problem. John seems to think I have a wiring problem as he has been supplying the Corvette drive-by-wire setup for awhile now.

Hopefully someone else has run into this problem and has a fix. I will just go over my wiring again and maybe wire it to dumby switches just to test.

I am happy with this setup and once I find my issue it will be completely working as designed.

Oh, I was just looking at your orange Stud very nice.

Stu Cool

iTrader: (13)

JD,

Which switch/turn signal are you using? How did you figure out which wire from the switch goes where? I have a couple different switches of different vintages, one with 3 wire and one with 4. My harness has 3 wires that go to the switch: On/off, set/coast, resume/accel and one to the brake pedal switch. I have been playing around with the switches with an Ohm meter, but still not sure which wire corresponds to which function.

Pat

jdperk-86elco

Since I did the swap in my 1986 El Camino I have a wiring diagram for my cruise circuit. My cruise switch is the standard GM style switch that is used through out most of their cars. My custom harness was made by SpearTech which tagged the wires to which function they went to so all I had to do was tap into my harness under the dash. What I did was find a location to not impact my dash wiring drastically and since my car already had the original cruise components I used the plug going to the old cruise electronics to tie in the wiring.

So if you use a GM stalk switch the wiring diagram from any GM should work also since it snakes down the column you could get a matching connector female end from another donar car.

Another solution could be to come up with your own switches since the cruise function is pretty simple.

G-Body

iTrader: (4)

This is a diagram for the 4 wire GM cruise switch, but if you are having trouble getting the switch to work, check the wires as they exit the stalk, I have had to replace a bunch of these switches because the wires were cracked as they exited the switch.
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jdperk-86elco

Well here are my results so far, I just purchased EFI and I have been emailing Paul from EFI about how I can see the stalk switch and brake pedal inputs and he gave me a solution. My PCM is from a truck so Paul gave me a custom file that would allow me to see GM.State15 and GM.State16 PIDs which show the stalk switch inputs. I still had to change my VIN to a Corvette VIN to get it to respond correctly.

So I was able to prove my stalk switch and cruise brakes disengage switch are all working as designed; however the TCC brake switch is showing Applied all the time. I double checked my TCC brake switch and NC I get 12V and brake applied I get 0V so my car side wiring and brake switch is good, but I get 10V on the PCM wire all the time. I even cut my spice to isolate the PCM wire and it still has 10V on it, and it will not light a 28Vdc test light (from my Air Force aircraft days.)

Is this leakage current showing this voltage on my DVM?

Could this PCM output be bad?

Could a pin be bent bleading over to this input?

Any Ideas on how I can proceed further?

On another note:
My Corvette manual shows this input to be NO and applies 12V when the brake is applied is the logic of removing voltage when the brake pedal is applied backwards?

There is also showing an Extended Travel Brake switch pin?

James

Stu Cool

iTrader: (13)

In my wiring diagram from Speartech it says the Lt Blue wire from the cruise control is supposed to go to the normally Open Brake switch (same as wire to brake lights). So you should have no voltage until the brakes are applied. Same as specified in the Corvette manual. Sounds like you have it wired to the wrong side of the switch. The voltage that comes on when the brakes are applied cancels the cruise control. I simply splice my wire into the wire going to the brake lights. I am looking at my (corrected) notes written on my instructions, and I had it backwards to begin with too.

Try switching the wire to the other pole of the switch and see if it works, should not take long to find out.

Pat

jdperk-86elco

Pat,

There are two brake switches one NO (blue wire) and a purple wire for the TCC lock up. My issue is with the TCC lock up brake switch wire. By Speartech directions the purple wire is NC (12V) and opens when the brake pedal is applied. I am using a 4l60e automatic transmission.

jdperk-86elco

See new thread named "PCM pin output voltage issue, could the PCM be bad? "

Stu Cool

iTrader: (13)

Yes that's right, but isn't that related to the Torque converter lock up rather than the cruise control? My understanding was the purple wire was to release the Torque Converter lock up Clutch, by removing voltage, when the brakes are applied. Actually, there are two wires, purple and pink that go to either side of the switch. You have not mentioned a pink wire, have you got one connected somewhere?

The Blue wire tells the cruise control to let go by applying voltage, also when the brakes are applied. On my set up I have a single brake switch with two opposite functioning connections, rather than two complete switches.

Pat

jdperk-86elco

Pat,

You are correct that TCC brake sw is for the torque converter lockup however the cruise is locked out because it checks this input also since both the TCC brake switch and cruise disengage brake switch should be actuated at the same time. I would think that if the torque converter lockup would be inportant for the cruise to work properly.

James

jdperk-86elco

Guys,

I think I found the problem but I need to confirm. I traced the purple TCC Brake switch wire to the PCM blue connector pin 34. Should this input be connected to pin 33? The PCM is 2002 PCM I think?

Looking at the top for pin assignments I see different versions and it appears that blue connector pin 34 changes for different years.

Ok, so if I do need to switch this pin what tool do I need and where can I purchase one? For that matter where can I also purchase pins and a crimp tool for future additions?

James

G-Body

iTrader: (4)

My 99 and 01 pin outs show that the TCC wire goes to pin 33. It is not a big deal to swap it, no special tools are required. Just pop the blue part of the connector off, and then lift the plastic tab above the metal pin and the pin will slide out of the back of the connector. It is kinda hard to explain but very easy to do, I`d take a pic but its dark outside . I don`t know where you could get pins other than at the dealer, I used a couple pins from the junkyard from a mid 90`s FWD piece when I needed extra pins. As for crimpers I always just use needlenose on all these special pins, takes a little more time but it saves me from having to spend $$$ on all the different crimpers.

jdperk-86elco

Guys,

The final fix was to move the TCC Brake Switch purple wire from pin 34 to pin 33. It was an honest mistake on the harness builder, I am just glad it was something simple.

I was able to see all things switch properly using EFILive. Thanks to Paul of EFI who gave me a new file that openned up the cruise control inputs so I could see them switch and help me troubleshoot it properly.

John at SpearTech has been patient with me trying to solve this cruise not working issue. His support with answering my questions was great.

Now to start seeing what I can tweak with EFILive. One of the first things will be to reset my Tach to read properly.

Problem solved!

Stu Cool

iTrader: (13)

Great news! Glad you got it sorted out

Pat