Some of these systems have the cruise stalk wired to the cruise module. Others are wired to the PCM. Please post what year/model your engine came out of, and do the same for the cruise module you used.
Joe
in fact those unit are very stand alone the "J" wire don't really need to be connect to the ECM, if you have DBC and have access to a VSS and TCC connection any EFI will work!
this is quote from a old truck forum: "I made this diagram for Clyde65, but thought others might be able to use it. This is just a schematic drawn to hopefully be a little clearer than the factory service manual. This is how to hook up a factory cruise control module for cable throttle body's. It's really fairly simple, you just need to make sure you get the right module. I personally used one from an Astro van, but mid 90's and up S-10's use the same module. The one you want will NOT have a wire in the "H" terminal of the module plug (see 2nd pic, notice the missing wire in the middle). Once you have that you'll need a 4 prong brake light switch, it will have 2 normally open and 2 normally closed terminals. These can be found in alot of 70's and up GM cars and trucks.
To run the factory cruise you need a 4000 pulse per mile signal. This comes straight out of the PCM, it's the signal to the speedo, radio ect. On a '99 to '02 truck, and F bodies it's the C2 connector (the red one) pin 50 dark green/white. The one at C2 49 is a 128k ppm and is only used for ABS, Don't try to use it.
You'll need a 4 wire cruise control switch to turn it on and off. If you have a '83 or newer column and it has cruise on it, it should be a 4 wire. For older columns that use a single screw to hold the turn signal lever the '81-'82 trucks and vans have a lever that can be converted that will work. I posted a "how to" here.
http://67-72chevytrucks.com/vboard/s...=cruise+switch
Other than that it's a matter of hooking up the cable to the TB and mounting the module.
This will work on almost any EFI engine that has a 4k PPM speed signal so if you have a TPI, LT1, or LS, all GM's use that signal.
I have this same set up on my own car and have about $50 max in the whole thing, and it works way better than the aftermarket cruise I have on another car. this cruise works flawlessly! set it and it stays there and doesn't fluxuate like the aftermarket."
hope that can help other here! thx everyone!