DBW Cruise Issue

[Hart_Rod]

Originally Posted by ls1nova71

You don't need to wire up the relay to act as a relay. You can use just the coil side of it wired to the cold side of the brake light switch and ground, the cruise will see it's ground through the coil and allow it to work. This is how I do mine and they work perfectly. I use micro relays, solder the wires to the terminals and tape it up in the harness. You can see a pic in my build thread post #122
http://ls1tech.com/forums/conversion...-c-10-a-7.html It's doing the same thing as a resistor, but they don't get as hot as a resistor can get.

Thanks! I keep forgetting how awesome that build thread is!!! Any one that is doing an LS install should really read through this thread several times, .

[thomasrepair]

Originally Posted by dayj1

I'm not aware of the ability to enable/disable cruise in the tune. If you're sure that your wiring is correct and that you have the resistor wired in correctly, it could be your VSS. Is the VSS sensor installed in the trans and connected to the PCM? Are your gear ratios, tire sizes, etc correct in the tune?

I've been following this thread and the only thing I havent verified from my cruise not working is what you suggested about the VSS. My speedo is working , but i'm not sure how the test for a signal at the PCM. Would I just test the wiring for continuity from the VSS to the PCM? I would have to figure which pin gets the input. Could a code reader confirm this signal?
My truck has a 2005 LS DBW, 6spd mtm from a CTSV. I dont have access to HP tuners, but feel this might be next. Any input would be appreciated.

[ls1nova71]

Originally Posted by thomasrepair

I've been following this thread and the only thing I havent verified from my cruise not working is what you suggested about the VSS. My speedo is working , but i'm not sure how the test for a signal at the PCM. Would I just test the wiring for continuity from the VSS to the PCM? I would have to figure which pin gets the input. Could a code reader confirm this signal?
My truck has a 2005 LS DBW, 6spd mtm from a CTSV. I dont have access to HP tuners, but feel this might be next. Any input would be appreciated.

Are you using just the Caddy trans or the whole engine and trans combo from it? What PCM and wiring harness are you using?

[thomasrepair]

Thanks for responding, I'm using the engine and trans from The caddy. The harness is from Howell. They put together the pcm, tach module, pedal, maf, throttle body from what would likely come from a 5.3 in a truck(long story) They programmed the LS6 fuel maps into the truck pcm. I'm running an Autometer electric speedo.
The cruise switch is from Rostra and wired through relays with results at the tach module harness connection as follows:
pin 14 brown =12v power with key on.
pin 4 dark blue=power when set button pushed
pin 5 gray=power when resume button slid over
pin 6 lite blue=power when brakes are applied
Standard tail lights, no led's
Help!!!

[thomasrepair]

Update!!!
I don't get my hands on code reader's too often, but i just did a live data scan and found out my VSS is reading at half actual vehicle speed. I thought OK it thinks I'm not going fast enough to set the cruise. I promply went looking for somewhere to go at least 80-100 he he. Well it didnt set at 90 so im back to the drawing board. I do believe this will need reprogrammed, but not sure if its related to the problem. My Yukon sets at 25mph. At least i know the vss signal is reaching the pcm.

[solidaxel]

Following, maybe I will learn something!

[ls1nova71]

Originally Posted by thomasrepair

Thanks for responding, I'm using the engine and trans from The caddy. The harness is from Howell. They put together the pcm, tach module, pedal, maf, throttle body from what would likely come from a 5.3 in a truck(long story) They programmed the LS6 fuel maps into the truck pcm. I'm running an Autometer electric speedo.
The cruise switch is from Rostra and wired through relays with results at the tach module harness connection as follows:
pin 14 brown =12v power with key on.
pin 4 dark blue=power when set button pushed
pin 5 gray=power when resume button slid over
pin 6 lite blue=power when brakes are applied
Standard tail lights, no led's
Help!!!

Might need to hear the 'long' story. A CTS-V doesn't use the brake pedal switch on pin 6, they use pin C1 62 that goes to an extended travel brake switch. Are you sure you have a truck tune, TAC, pedal etc?

[thomasrepair]

Thanks again for your time and interest. The long story for the harness goes like this. I had Howell build the harness and program the pcm. I installed it, but all it would do is start and idle. they had me send them the entire system to bench test. They were stumpted. They offered to swap my CTSV components for the truck parts. I took the deal. They rewired the harness(blue/green connectors), reprogrammed a pcm, new tach module, accell pedal and throttle body. The MAF is original CTSV.
It all looks like parts from my 2004 silverado 5.3L which is the configuration they built it around from what i was told. In fact I have swapped the tach module from the 5.3 for a test, but it didnt fix the cruise. The components should all match as far as I can tell, but with all the changes its anyone's guess. I've made one call to get help from Howell, but so far all i've gotten is a schematic for the switch. I know this is as real cluster and harder than it should be to trouble shoot. They built it to be a truck setup with the 2002 vette LS6 tune.

[ls1nova71]

There are two brake light switch wires that need to be hooked up, do you have them both hooked up? One hot when brakes applied and one hot with brakes not applied.

[thomasrepair]

I only knew of the one brake light wire. Its lite blue and comes from pin 6 at the tach module and is connected to the cold side of the switch. All the harness wires were tagged and accounted for. I have verified ground ay the switch back through the brake light bulbs and also by wiring in a tempoary 3rd brake light.

[ls1nova71]

There should be a purple wire on pin 33 of the blue connector that needs power with the brakes not applied, do you have that hooked up?

[thomasrepair]

Am i to understand that the purple wire leads from the pcm and terminates at the brake switch cold side? Would this be instead of the pin 6 from the tach module? I won't be able to check this till next week, but i will definetly look for that wire!!! I appreciate your help and can only hope you continue to enjoy a good challenge.

[thomasrepair]

I reviewed your post and I will check for power at pin33 when the brakes are not applied.
Thanks

[ls1nova71]

You'll need a 4 prong brake light switch, the kind used for cruise control in the 70's and 80's. They have 2 sets of contacts, one normally open and one normally closed. The TAC ties into the cold side of the brake light wiring and the PCM side will be the other set that needs ignition power and will send power to the PCM when the brakes are not applied.

[72MARIO]

Make sure when you adjust the brake light switch that the tcc wire has power in and out without the brakes applied.

I had a problem.with the cruise not working. Turned out I had to push the pin in further. Into the barrel of the switch to make contact. Doing that I now have to push the brake pedal down further for the brake lights to come on

[thomasrepair]

Originally Posted by ls1nova71

You'll need a 4 prong brake light switch, the kind used for cruise control in the 70's and 80's. They have 2 sets of contacts, one normally open and one normally closed. The TAC ties into the cold side of the brake light wiring and the PCM side will be the other set that needs ignition power and will send power to the PCM when the brakes are not applied.

Ive been away from the cruise diagnosis. No i didn't crash my truck trying to set the cruise at 90+, LOL. Job change, out of state trip etc.
Anyhow I went to check power at pin 33 of the blue PCM connector and I don't have a wire there. For reference I have another harness for my 5.3 4L60E build and it has that purple wire in blue33 tagged for TCC. Would I still need that wire with my manual trans?
I did pick up a 4pin brake switch, but not sure how to wire it since I don't have the purple wire?

[ls1nova71]

Yeah, for the cruise to work, I'm pretty sure you need both of them hooked up. There are certain parameters that need to be met each ignition cycle for the cruise to work and its those two wires that it uses to make sure the brake switch is functioning correctly. On a manual transmission that wire would be hooked up to a clutch pedal switch so that when you push in the clutch it disengages the cruise, otherwise it will likley bounce off the rev limiter when you push in the clutch. You can hook it to the brake light switch though as long as you remember to shut the cruise off before using the clutch pedal.

[thomasrepair]

Originally Posted by ls1nova71

Yeah, for the cruise to work, I'm pretty sure you need both of them hooked up. There are certain parameters that need to be met each ignition cycle for the cruise to work and its those two wires that it uses to make sure the brake switch is functioning correctly. On a manual transmission that wire would be hooked up to a clutch pedal switch so that when you push in the clutch it disengages the cruise, otherwise it will likley bounce off the rev limiter when you push in the clutch. You can hook it to the brake light switch though as long as you remember to shut the cruise off before using the clutch pedal.

Sounds like i have half the battle fought since I already have a clutch pedal switch wired into the start circuit.
So for safety what you are suggesting is for 12v at a clutch switch going to pin 33 interrupted by pushing in the pedal which shuts off cruise. So before I add that switch I should be able to test for cruise by adding that hot wire directly to pin 33?
When that makes the cruise activate I will gladly wire in that double brake switch on my clutch pedal to activate/deactivate the normally open and normally closed functions for a safe, permanent install.
I will report the outcome.
Thanks again for your expertise.

[ls1nova71]

Originally Posted by thomasrepair

Sounds like i have half the battle fought since I already have a clutch pedal switch wired into the start circuit.
So for safety what you are suggesting is for 12v at a clutch switch going to pin 33 interrupted by pushing in the pedal which shuts off cruise. So before I add that switch I should be able to test for cruise by adding that hot wire directly to pin 33?
When that makes the cruise activate I will gladly wire in that double brake switch on my clutch pedal to activate/deactivate the normally open and normally closed functions for a safe, permanent install.
I will report the outcome.
Thanks again for your expertise.

You cant just put power to that wire and have it work, you would need to momentarily remove the power after starting the truck. The system monitors the brake switch each ignition cycle, and if it doesn't see you press the brake pedal at least once, the cruise is disabled. I have personally tried it on my truck, with a perfectly good working cruise, if I start it and put it in gear without applying the brake, and drive it fast enough for it to set, it doesn't, but one tap of the brake pedal and it works fine again. GM built some failsafe into the system.

[thomasrepair]

Originally Posted by ls1nova71

You cant just put power to that wire and have it work, you would need to momentarily remove the power after starting the truck. The system monitors the brake switch each ignition cycle, and if it doesn't see you press the brake pedal at least once, the cruise is disabled. I have personally tried it on my truck, with a perfectly good working cruise, if I start it and put it in gear without applying the brake, and drive it fast enough for it to set, it doesn't, but one tap of the brake pedal and it works fine again. GM built some failsafe into the system.

OK you lost me. Brake switch or clutch switch?
Wouldn't the clutch switch work for the momentary power interruption? Every time i shift up to cruise speed a clutch pedal swing could cycle the power.
Anyhow can I impose on you to describe how to wire this.

[ls1nova71]

Sorry, brake switch or clutch switch, depending on automatic versus manual. What I was getting at was you saying you could just temporarily hook up the wire to power. You can, but you will need to interrupt the power at least once during the ignition cycle for it to operate. Hope that clears it up?

[thomasrepair]

OK great, so my temporary setup won't be that easy. I might as well wire up the double switch at the clutch pedal to create the momentary circuit and have that end done. Should be fun.
Thanks again

[ls1nova71]

what kind of switch are you using on the clutch pedal for the starter interrupt? you may need to add a starter relay to it since both the starter and cruise pin 33 are going to be using the same switch, which wont work because the PCM needs power whenever the ignition is on and the starter obviously only needs power during cranking.

[thomasrepair]

Originally Posted by ls1nova71

what kind of switch are you using on the clutch pedal for the starter interrupt? you may need to add a starter relay to it since both the starter and cruise pin 33 are going to be using the same switch, which wont work because the PCM needs power whenever the ignition is on and the starter obviously only needs power during cranking.

Currently my clutch switch is wired to interrupt the 12v ign. needed to trigger a starter relay. I thought I would use a (brake switch/w cruise) which will have both circuit needs covered. For starter interrupt it's (open) until the pedal is in.
The cruise side is (closed) until the pedal is in.This gives you 12v ign. to pin33 interupted when you shift.
What do you think?

[ls1nova71]

Yep, that should work. I was thinking backwards the other day....