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Hello, I am finally to the point of hooking up my ac and cruise on 95 full size Chevy, I have completely removed the 95 computer and I am wondering what you guys have done with the dark green signal wire that went to the 95 ecm for the ac and the blue with black stripe wire that goes from the cruise to the 95 ecm. Did you guys hook them to the ls ecm or convert them in to complete stand alone? Thanks
Subscribing for info! I also have to hook up cruise on my 95 and am wanting to add the A/C request signal to bump up idle.
Here's a thread with good info.
http://ls1tech.com/forums/conversion...-solution.html
I think I will hook up a 12V signal when a/C button is pressed to the A/c signal request on the new PCM. Hopefully that will bump up idle.
On the cruise, I spliced dark green (to speedo) and dark green with white(to cruise module) together in hopes that that will provide the correct speed info to the cruise. My plan is to then connect the lt blu/blk wire to the pin 13 on red connector for a 99-02 pcm which is the cruise control engage input.
Also, I plan on keeping ABS by connecting pin 49 on red connector (128K vehicle speed output) to the brake pressure modulator valve white wire. Not exactly sure if this will all work, just what I have gathered might work from looking at wiring diagrams. please post on what you attempt and if it works. I will do the same, although I wont get to it for a few months.
I am just wondering if the ac will work without the ac signal, it doesn't seem like the ac clutch would kick in at all without the other side of the circuit.
You're using the stock 95 A/C right? If so, it should work as it did before as long as you kept the wiring for it. Is that what you're wondering? It should still work without the A/C request signal to the new PCM. It's not the old ECU that activated the A/C. The wire to the ECU just told it to raise the idle AFAIK.
Thats what I thought, but I wasn't sure, yes I kept the OE ac wiring all intact, I don't have ABS anymore, and the only other issue is the one signal wire for the cruise, but I don't think that is going to be to bad, I may use your idea above on mine too.
I have gone through my oe harness and removed all the extra wires except what is needed, I am integrating the ls harness and it in to one harness, I don't want anything extra.
As far as i know this will not work as the new pcm does not use 12v signal for ac request which is why this is somewhat of an issue for the older trucks. The new pcm im pretty sure uses serial data so i would think 12v to it might casue some issues....possibly expensive.... i just kept it wired like it was (with the exception of adding electric fan relays) and when the ac button is pushed or the knob is turned to defrost, that will trigger the pump coil to engage. The motor should (like mine and several others ive seen) sense the drop in rpm and kick it up a bit to keep from stalling and drop back down when ac is shut off. ive had no issues with it.Quote:
Originally Posted by Jeebalow
I got that information from the link I posted above the line you highlighted in red. Post #13 has the wiring diagram for an 02 camaro. The HVAC sends a 12V signal to the ac request according to that. Take a look:Quote:
Originally Posted by kewljay223
http://ls1tech.com/forums/conversion...l#post16616051
ok well i got my information from this thread, http://www.ls1truck.com/forums/lsx-t...tegration.html when i did my a/c a year and a half ago and it hasnt been updated yet. If you read through that, youll see that the guy in your link setup works because he is using the older 99-02 pcm which utilize the 12v signal. I got screwed on my end because i have an 03 and all 03+ use serial data from the HVAC unit which i doubt you will be able to replicate from some DIY stand alone unit. NOW im not sure which pcm you or DRAGGIN are using. if you guys have the older one, then you can both disreguard this post. but if either of you have the newer one like me, just keep it the way it was wired originally through all the pressure sensors and you should be good to go. the new pcm will sense the load and bump the idle up anyway. IF you are using E-fans, then you will need to get creative with relays like i did for them to kick on high like they are supposed to which is completely doable. my setup works great so far. Last option, be the first person to find a tuner that can change the input settings inside the pcm from serial data to discrete (good luck). IF YOU DO FIND SOMEONE, PLEASE POST!! anyway, hope that clears up my previous post.Quote:
Originally Posted by Jeebalow
I am using an 01 PCM so I should be good to go with the info in the link I posted, but you make a great point. DRAGGIN may not be able to use the same method.Quote:
Originally Posted by kewljay223
I am using 06 silverado fans and harness. I will activate the fans with the a/c clutch engagement and/or the a/c button in the cab. From what I remember form thermodynamics and heat transfer, a steady stream of air would be better to dissipate heat rather than only when the clutch engages. I was also thinking about using a controller so the fans will not come on above 45 MPH because of the A/C (the PCM would still control them based on engine temp).
Hello, I using a core 411 PCM from Nelson, set up to be like 98-02 ls1 computer, I am planning to just use the ac in standalone mode and try it like that. Now it's only the cruise left to deal with.
If your using the cable tb just hook it back up to the tb. Mine works fine on my 97. I'm going DBW now so I'll figure something out.
Well, it looks like the simplest way for cruise control so far is to use the Dakota Digital CRS-3000 that works with the gas pedal. I'm sure there's others out there but this one is proven.
This would work if we had kept the old ECU. Unfortunately, both Draggin95 and I got rid of it and are trying to have the new PCM do all the work. So it's a matter of providing the cruise module with the same information the old ECU provided it to have it work.Quote:
Originally Posted by NITROUS
I'm going to an e38 ecm and haven't found anyone who's made it work right but I'd like to follow this thread just incase someone does. I'm trashing my 411 because the e38 does so much more. Btw, nice to meet you, I haven't posted in a while. If I find a way I'll be glad to post it. I just need to look at some more schematics.
Nice to meet you too! I don't post too much either. I wasn't aware of the E38 and it's advantages. I'll have to do some more research into that. Please post what you find. i will do the same for what we are trying to do once I get more time to work on this.
Jeebalow, I'm not sure which ended you're using but I found out a 411 won't control the cruise control on a 6/l80 or 90 it has to be an e38 with cruise module to the pedal. Let me know if you find something but this info came from GM. Thanks
ECM, not ended. Durn phone spell check.
I am using a 01 ECM. I am pretty sure it is a 411. I also have a manual trans so I do not have to worry about the trans. I know nothing about trans wiring or tuning for this reason. Sorry
Did a little more searching. I think i can shed some light but a bit confused on how your set up. you say you removed the old ecm. ok thats fine. but what about the DRAC module? did you toss that too?? If so then i see what the dilema is. But if not, then you still should have the wire that goes to the cruise module because im 99% sure the DRAC is what sends that signal, not the ECM. The DRAC sends 2,000 digital pulses per mile to the ECM (Electronic Control Module), 4,000 digital pulses per mile to the cruise control module, and 128,000 digital pulses per mile to the ABS (Anti-Lock Brake) computer. Your only loss from tossing the old ecm is the speedo signal but the new one can do that provided you "T" into the VSS signal for the new pcm (which i did and it works fine).
So to clear up, they way i understand it, make sure you
1)have the twisted yellow/ppl wires from VSS going to both the DRAC and the new pcm.
2)still have signal wire from DRAC to cruise module (should still be hooked up unless you know you cut it)
3)have speedo hooked up to output of new pcm
4)and obviously still have the 3 or 4 wires from control lever/TCC to cruise unit
i assume you both have #3 done already and im betting # 2 and 4 are still connected. im also betting you cut the twisted pair from vss and put them on the new pcm. i think if you just T off the twisted pair back to the cut pair from inside the cab, this will solve your problems. just make sure to twist the two wires your going to add to cancel out any EMF that the vss creates (the reason they are twisted from the factory).
NOW, if you tossed the DRAC also, well then i still think your ok. If i understand what jeeb was saying on how he plans too hook it up (when you say splice, you are talking about "T-ing" into the wire from pcm to speedo right?), that SHOULD work as the pcm sends out a 4k ppm signal from the factory. and as stated, the cruise wants a 4k ppm signal also. BUUUUT, if you change your gears or tires, you will now need to change the tune to compensate and im not sure how that affects the output. Does changing the the tune change the actuall signal higher or lower going to the speedo? or does it modify the input to output ratio within the pcm to still output 4k ppm no matter what? if so great. but if it changes the actual output, seems to me the speedo will be correct but that means you will be sending a higher or lower ppm to the cruise in which case i have no idea how well it will like that.... may or may not be ok...
Sorry for the long post. I hope it was clear enough. lol But if all else fails i came accross this and I thought of this thread instantly. I havnt checked out the dakota digital part that NITROUS mentioned but ive been on their website before and wow... great stuff but PRICEY!! anyway, if you cant get it to work wiring it the way you described and 200 bucks is worth having cruise.... then check this out....
http://www.summitracing.com/parts/rpc-250-1223
or this little bad boy for a bit less might work http://www.dakotadigital.com/index.c...rod/prd126.htm
Just some ideas
Great information, what ecm are you using? Williams Performance said it could be done with a newer ecm also but couldn't tell me how to do it. I'll take your info and try to figure it out on mine. They did say I had to tie into the corvette pedal I'm using. Thanks
Exactly. That is what my plan is. 4K PPM to speedo/cruise (I didn't know whether the cruise needed 4K or not so thanks for confirming!). And 128K PPM to ABS. When you correct for gears and tire diameters, you are essentially telling the ECM how many full cycles of the sine wave from the VSS (the number of trans output shaft rotations) are in a mile. It then uses that data as well as time and calculates speed. So when you correct for gears and tires it corrects the signal to Speedo, Cruise, and ABS. Then there is no need to keep the DRAC (I tossed it when I found I can get the same data from the LS PCM) Thanks for looking into that!!Quote:
Originally Posted by kewljay223
Ok, after more research I was told my e38 won't control the cruise control because it has to run through the vette BCM. If I had a 411 with seperate TAC module I'd only have to tie in 3 wires. I was told wrong so disregard what I said about the E38 unless someone knows different.
Im using the 03 pcm that came with my motor and DBW. so all i had to do was hook the lever control wires (like 4) to the TAC module and i was done. thats why im not sure why people are so afraid of it. Its so simple. But to each their own. Anyway, glad i could help out. hopefully that works out for you guys. you should update this either way to confirm or deny that it works.
I think most just get overwhelmed with the thought of wiring and never give it a shot. I will definitely update once I get going on my swap again.
DBW for me wasn't intimidating at all considering how simple it is once you put in a little time and look at a couple wiring diagrams. I'm really glad I decided to stick with it instead of abandoning ship for a DBC setup like a lot of guys. People complain about a throttle response issue but for me that would only come into play if I was looking to minus a few tenths off of my ETs at the track and my big 4x4 is obviously not a race truck. If anything, my throttle is almost too responsive, especially considering how much power I have compared to before with the 350. My wife said when she drove it "it feels like it launches every time you leave a stop light and you have to be careful with the gas pedal"LOL. When I go to a different setup with a bunch of go-fast parts like a stroked out 408 with cnc heads and high flow intake (maybe a bottle) then I'll worry about simplifying my throttle situation.Quote:
Originally Posted by kewljay223