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Old 01-20-2019, 05:22 PM   #71
GMC Guy
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Join Date: May 2009
Location: Sparks, NV
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Re: 5.3L DBW cruise hookup

Quote:
Originally Posted by jks67ss396 View Post
Bump for wiring clarification:

i finally found a 4 wire cruise lever that wasnt beat to hell and back. its from a 74 van. definitely factory looking. could be aftermarket, but it was ran inside the factory column, under the factory cover, under the factory wiring.

wires are red, green brown and yellow

after pulling the assembly apart, i ohmed everything out

red goes to the middle connector/appears to be 12V power

brown tied to red when slider is on/appears to be cruise on/off

green is the set speed push button. tied to red when slider is on, but not when speed button is pushed, ie normally closed/connected to 12V

yellow is only tied to red when slid to resume

unlike ackattack (post 8, when pushing the set speed/green wire, there is no contact with the yellow wire. obviously, when i do slide to resume, there is continuity between yellow and green because green is normally connected to red when cruise is on, and sliding to resume, contacts yellow to red, so by default, yellow and green are connected "through" the red wire, but thats not the same functionality as ackattack.


Since the LS DBW requires "set speed" pushbutton to be normally open, momentary close I too will use relay to invert the set speed functionality, but i believe the resume function is fine, so ill only use 1 relay.

some background for others wondering:
I wire relays a little different than Ackattack
I use pin 30 as relay "signal" power
i use 85 as relay control positive
i use 86 as relay control ground
87a would be normally closed (when relay is off, 87a and 30 are connected).
87 is only connected to 30 when the relay is energized.


So when relay is powered on (brown/cruise "on" wire will provide input power to relay... pin 30...only powered when cruise is on), the green set button (connected to relay 85, again only powered when cruise is on), will keep relay energized and the output set to 87 (which is connected to nothing) and only when green set button is pressed and the relay is de-energized, will the relay go back to pin 87a, and the path from 30 to 87a will be complete, sending 12V pulse to the set wire on the tac module

again, my cruise lever looks factory. id really like to know if GM ever used this "normally closed" set speed functionality or if its always been like ls1nova says

seems like others have found these same style levers, but i never saw their resolution...

i think this should work. let me know if there are any flaws in my thinking

thanks guys
Did this method end up working? I can't get Resume to work using the 2 relay system
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Greg
1974 GMC
1/2 Ton SWB Fleetside
L33 5.3/4l65e

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