DBW Cruise Issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jackyl9999 · 08-02-2015, 05:50 PM

I installed a cruise control setup today on my 70 gmc and it will not activate.

I used the parts and method in this post by ACKATTACK.

http://67-72chevytrucks.com/vboard/s...d.php?t=398006

I checked all the relays and they are working as shown in the above thread. I double checked my wiring from the TAC module as well. It will not turn on (I can hear the relays though) or respond in any way.

Any ideas for what I need to look for?

jackyl9999 · 08-03-2015, 10:06 AM

Also, I am using a GPS speedo, if this has anything to do with the issue.

ls1nova71 · 08-03-2015, 03:11 PM

Have you verified that you are getting a constant 12v at the 'on/' wire pin 14 on the TAC? Orher than that, make sure you have the brake switch adjusted properly.Also, make sure pin 6 is hooked to the brake light switch that is hot when the brakes are applied. You dont have LED tail lights do you?

jackyl9999 · 08-03-2015, 07:40 PM

Yes I do have Led Tail lights.

ls1nova71 · 08-03-2015, 09:27 PM

Quote:

Originally Posted by jackyl9999

Yes I do have Led Tail lights.

Try swapping them out for a pair of 1157's and see if it works. The cruise needs to see ground through the brake lights and LED's won't do it so it usually won't work. If that fixes it, you can add an extra 'artificial' load to the circuit to allow you to run the LED's.

BR3W CITY · 08-04-2015, 12:48 AM

Quote:

Originally Posted by ls1nova71

Try swapping them out for a pair of 1157's and see if it works. The cruise needs to see ground through the brake lights and LED's won't do it so it usually won't work. If that fixes it, you can add an extra 'artificial' load to the circuit to allow you to run the LED's.

Ya some guys will dangle an 1157 somehwere hidden to create load, but thats a short/fire hazard. You can get little resistor packs that create the same load for a few bucks online, and some folks just make em.

BR3W CITY · 08-08-2015, 11:58 PM

I think for all intensive purposes, the engine and computer don't care if the truck is in cruise, at least with GenIII engines. Its possible GENIV is different because of DOD's use in cruise, but other than that...its not like there's "cruise" setting or anything.

Daaaanz67 · 08-09-2015, 12:33 AM

Double check the adjustment on that brake switch, I was stumped with mine and slowly backed the switch away from where it bottoms out and started working. Worth a try.

aknovaman · 08-09-2015, 08:32 AM

Stop guessing without real data. You guys are funny. You throw suggestions out like popcorn. What's next, replace the gas cap?

OP, go find someone who has HP tuners, datalog what the inputs and outputs are doing and troubleshoot it logically with real data. Otherwise you are just guessing.

In hpt, the satus bits will tell you if the switches are commanding cruise, brake pedal status to the PCM and it will also tell you if the output is enabled among other things.

aknovaman · 08-09-2015, 09:49 PM

If you really want this thing to work, pm me your phone number and I can talk you through troubleshooting it over the phone with a simple voltmeter.

jackyl9999 · 08-10-2015, 08:15 AM

I am going to drop by and have my tuner take a look at it with HP tuners.

**Hart_Rod** · 11-24-2016, 11:51 AM

Quote:

Originally Posted by jackyl9999

I am going to drop by and have my tuner take a look at it with HP tuners.

Did you ever find a solution to this? Please post. TIA.

Big Port Jimmy 6 · 11-25-2016, 09:19 AM

I've always used a relay with LEDs and cruise.

LED Tail Lights Note

The use of LED tail lights requires a five-function automotive relay to bypass the brake system. LED tail lights do not let the violet wire (cold side of the brake switch) see ground through the brake lights, themselves. Wiring in a relay is as follows:
http://www.rostra.com/manuals/250-4382_Form5260.pdf

**Hart_Rod** · 11-27-2016, 09:48 AM

Quote:

Originally Posted by Big Port Jimmy 6

I've always used a relay with LEDs and cruise.

LED Tail Lights Note

The use of LED tail lights requires a five-function automotive relay to bypass the brake system. LED tail lights do not let the violet wire (cold side of the brake switch) see ground through the brake lights, themselves. Wiring in a relay is as follows:
http://www.rostra.com/manuals/250-4382_Form5260.pdf

I was able to wire a regular bulb into my 3rd brake light to verify that the LED tail lights were causing the problem, the CC works perfect now. I'm going to try one of the LED flashers and see it that will work before I wire in another relay, I already have a enough relays as it is under the dash.....

.

solidaxel · 10-08-2017, 03:40 PM

Following, maybe I will learn something!

72MARIO · 10-13-2017, 07:43 AM

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

08-02-2015, 05:50 PM	#1
jackyl9999 Registered User Join Date: Feb 2003 Location: Paragould, Ar Posts: 571	DBW Cruise Issue I installed a cruise control setup today on my 70 gmc and it will not activate. I used the parts and method in this post by ACKATTACK. http://67-72chevytrucks.com/vboard/s...d.php?t=398006 I checked all the relays and they are working as shown in the above thread. I double checked my wiring from the TAC module as well. It will not turn on (I can hear the relays though) or respond in any way. Any ideas for what I need to look for? __________________ 1970 Gmc Grande Sierra Swb 2wd LSX (LQ4/4L80e) 1990 K1500 Daily

08-03-2015, 10:06 AM	#2
jackyl9999 Registered User Join Date: Feb 2003 Location: Paragould, Ar Posts: 571	Re: DBW Cruise Issue Also, I am using a GPS speedo, if this has anything to do with the issue. __________________ 1970 Gmc Grande Sierra Swb 2wd LSX (LQ4/4L80e) 1990 K1500 Daily

08-03-2015, 03:11 PM	#3
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: DBW Cruise Issue Have you verified that you are getting a constant 12v at the 'on/' wire pin 14 on the TAC? Orher than that, make sure you have the brake switch adjusted properly.Also, make sure pin 6 is hooked to the brake light switch that is hot when the brakes are applied. You dont have LED tail lights do you? __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

08-03-2015, 07:40 PM	#4
jackyl9999 Registered User Join Date: Feb 2003 Location: Paragould, Ar Posts: 571	Re: DBW Cruise Issue Yes I do have Led Tail lights. __________________ 1970 Gmc Grande Sierra Swb 2wd LSX (LQ4/4L80e) 1990 K1500 Daily

08-08-2015, 11:58 PM	#7
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: DBW Cruise Issue I think for all intensive purposes, the engine and computer don't care if the truck is in cruise, at least with GenIII engines. Its possible GENIV is different because of DOD's use in cruise, but other than that...its not like there's "cruise" setting or anything. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

08-09-2015, 12:33 AM	#8
Daaaanz67 Registered User Join Date: Nov 2011 Location: Idaho Posts: 857	Re: DBW Cruise Issue Double check the adjustment on that brake switch, I was stumped with mine and slowly backed the switch away from where it bottoms out and started working. Worth a try.

08-09-2015, 08:32 AM	#9
aknovaman Registered User Join Date: Aug 2013 Location: Tecumseh Posts: 355	Re: DBW Cruise Issue Stop guessing without real data. You guys are funny. You throw suggestions out like popcorn. What's next, replace the gas cap? OP, go find someone who has HP tuners, datalog what the inputs and outputs are doing and troubleshoot it logically with real data. Otherwise you are just guessing. In hpt, the satus bits will tell you if the switches are commanding cruise, brake pedal status to the PCM and it will also tell you if the output is enabled among other things. __________________ Current project 1959 Willys = GEZR TRUK Geezer is a Latin compound word made up of two roots. Gee meaning Urine Stain and Zer meaning your pants are open! FMCDH GBU and GBA http://www.youtube.com/user/aknovaman/videos

08-09-2015, 09:49 PM	#10
aknovaman Registered User Join Date: Aug 2013 Location: Tecumseh Posts: 355	Re: DBW Cruise Issue If you really want this thing to work, pm me your phone number and I can talk you through troubleshooting it over the phone with a simple voltmeter. __________________ Current project 1959 Willys = GEZR TRUK Geezer is a Latin compound word made up of two roots. Gee meaning Urine Stain and Zer meaning your pants are open! FMCDH GBU and GBA http://www.youtube.com/user/aknovaman/videos

08-10-2015, 08:15 AM	#11
jackyl9999 Registered User Join Date: Feb 2003 Location: Paragould, Ar Posts: 571	Re: DBW Cruise Issue I am going to drop by and have my tuner take a look at it with HP tuners. __________________ 1970 Gmc Grande Sierra Swb 2wd LSX (LQ4/4L80e) 1990 K1500 Daily

11-25-2016, 09:19 AM	#13
Big Port Jimmy 6 Addicted to Rust Join Date: Dec 2009 Location: Abbeville SC Posts: 1,030	Re: DBW Cruise Issue I've always used a relay with LEDs and cruise. LED Tail Lights Note The use of LED tail lights requires a five-function automotive relay to bypass the brake system. LED tail lights do not let the violet wire (cold side of the brake switch) see ground through the brake lights, themselves. Wiring in a relay is as follows: http://www.rostra.com/manuals/250-4382_Form5260.pdf __________________ Current trucks: (48 GMC100 320 inliner) Gone (48 Suburban in pieces) Sold 87 GMC CCSB 5.3 4l60E Daily Driver ECTA National record holder XO/PP We never really grow up, we just learn how to act in public.

10-08-2017, 03:40 PM	#15
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: DBW Cruise Issue Following, maybe I will learn something! __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

10-13-2017, 07:43 AM	#16
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,051	Re: DBW Cruise Issue 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 __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD



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