GalDemSuga
1/2 ton status
I'm looking to fix the cruise control on my 89 K5. As of now, it doesnt work. When I push the buttons nothing happens. How do I go about troubleshooting this. I believe all the parts are there.
CK5
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Cruise Control
- Thread starter GalDemSuga
- Start date
FullNelson
Registered Member
Bump.
Where do you verify a signal being sent from the switch?
How can you test different components of the CC?
Where do you verify a signal being sent from the switch?
How can you test different components of the CC?
1st think I would check is all the vacum lines to make sure you have good vacum pressure.
Thanks all. Big blue is in the shop right now getting the driveshaft lengthened. as soon as I can see it I will be checking and rechecking vaccum lines, etc..... I can get a new cruise servo in a day if needed. Unfortunately I have feeling thats what I will be doing
GalDemSuga
1/2 ton status
awesome info
a common cause of no work is the adjustment of the brake switch. if it is not fully closed the cruise will not work.
FullNelson
Registered Member
Ive suspected it were the vacuum lines on account of the engine sounding like it bogs whn I engage CC. However I havent looked into it as its not a pressing issue. I was also wondering how you could electrically trace the CC circuit to eliminate that possibility
You can check the switch with an ohmmeter by disconnecting it from the control module under the dash. You should see continuity make/break when you push the buttons.
You could test the servo by disconnecting the throttle linkage and then running a vacuum line directly to the intake manifold (at idle). You could also test all of the vacuum lines to the servo and the little ball with a stethoscope or piece of hose.
Maybe it's silly to ask, but does your speedometer work? I think 89 was the last year for mechanical speedo and the cruise control uses an optical sensor in the back of the speedometer. By counting pulses it knows how fast the back of the speedo is spinning. This also may have come disconnected.
You could test the servo by disconnecting the throttle linkage and then running a vacuum line directly to the intake manifold (at idle). You could also test all of the vacuum lines to the servo and the little ball with a stethoscope or piece of hose.
Maybe it's silly to ask, but does your speedometer work? I think 89 was the last year for mechanical speedo and the cruise control uses an optical sensor in the back of the speedometer. By counting pulses it knows how fast the back of the speedo is spinning. This also may have come disconnected.
BubbaJ
Newbie
Cruise Control NONOP
So ive been trying to follow along with a couple different conversations across the internet on this topic. i have a 92 K5. i am about to head home after gettin out of the military and was hoping to fix my cruise before taking off on a 1900mile 55mph journey. ive had the truck roughly six months cruise hastn worked since ive owned it.Initially i had an intermittent ABS light. approaching 20mph it would come on and passing it slowing down it would go off. i replaced the brake switch after having read a couple similar articles. ABS light is gone. Still no luck getting the ABS to kick on however. Has anyone undergone this task and successfully accompished the repair. My maintenance manual seems very sparce with info regarding the cruis control save for a wire diagram with wires not matching what im seeing in the truck.
So ive been trying to follow along with a couple different conversations across the internet on this topic. i have a 92 K5. i am about to head home after gettin out of the military and was hoping to fix my cruise before taking off on a 1900mile 55mph journey. ive had the truck roughly six months cruise hastn worked since ive owned it.Initially i had an intermittent ABS light. approaching 20mph it would come on and passing it slowing down it would go off. i replaced the brake switch after having read a couple similar articles. ABS light is gone. Still no luck getting the ABS to kick on however. Has anyone undergone this task and successfully accompished the repair. My maintenance manual seems very sparce with info regarding the cruis control save for a wire diagram with wires not matching what im seeing in the truck.
Does this link still work?
http://dyeager535.topcities.com/cc.html
I can't get it to where I am now. I don't know a whole lot about the 1992 stuff, but I'm guessing it uses electric speedometer/DRAC (or some sort of buffer) and VSS on the tailhousing? The diagnosis is likely nearly the same, I would just not rely on wire color and ignore the VSS buffer stuff. I assume yours still has a vacuum motor cruise and not the electric motor?
http://dyeager535.topcities.com/cc.html
I can't get it to where I am now. I don't know a whole lot about the 1992 stuff, but I'm guessing it uses electric speedometer/DRAC (or some sort of buffer) and VSS on the tailhousing? The diagnosis is likely nearly the same, I would just not rely on wire color and ignore the VSS buffer stuff. I assume yours still has a vacuum motor cruise and not the electric motor?
I'll tell you why my CC didn't work when I bought my '89: in post #4 in this thread (on the top left most diagram), the piece that connects part #1 to part #14 was broken. I simply used a zip tie to reattach it.
IMO, check in this order:
#1 mechanical parts
#2 vaccum lines (this is important for more than just the CC function)
#3 brake switch behind pedal
IMO, check in this order:
#1 mechanical parts
#2 vaccum lines (this is important for more than just the CC function)
#3 brake switch behind pedal
BubbaJ
Newbie
dyeager353- It is actually an electronically operated cruise. The motor is mounted on the driver side firewall in the engine compartment. Before i swapped that brake switch, prematurely clandr1, the abs light would come on around 15mph. Now i hear the ABS kick on at that speed rather than seeing the light so apparently that needed replaced at any rate. The problem i was thinking would be with the cruise lever switch itself. I have a wht wire constand 12V coming from the switch with a PPL and GRY wire as well. Under no circumstances do either of the other two wires have power. Ive turned the key on and attempted to operate the switch to see if it changed the voltage in the ppl or gry wire and no go. What i gather on the brake switch is that the 2 wire side of that switch is cruise and are 0v until you depress the brake and they change to .1. I checked it wondering if it was out of adjustment and preventing the cruise from turning on but i sdjusted the switch as per the little chinese instructions so its iron clad. Additionally, after replacing the brakeswitch and hearing the abs kick in i felt what im hoping was the overdrive in my transmission kick in at cruising speed. new trans has been in for more than a month and thats the first ive noticed or felt that and i have a pretty keen sense for these things. Any input on that at all. seemed odd to me.
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How does the '86 wiring compare to the '92? The electronic setup you have takes the same input as the earlier stuff, I'd be pretty surprised if much other than wire color changed outside of vacuum vs. electric, so diagnostics are likely the same.
BubbaJ
Newbie
The only other components in the system to check aside from that brake switch would be the wires themselves, the lever switch or the electric motor. Im no electrician but i am pretty handy with a voltmeter when it comes to vehicles. Based on some of what i read on the earlier posts i should have switched 12v on one of the 3 wires coming from the switch itself but i do not. that would indicate to me the switch is bad. how would i verify wether the motor is go/bad. can i jump a 12v feed to it simply to see if it operates or is this gonna be a process of elimination kind of job.
BubbaJ
Newbie
Ok gents. So after some more in depth investigating i discovered why my switch seemed to be completely inop.....It was disconnected at the single large black wire. After pluggin it in i found that the switch is not perfectly functioning but i can engage the cruise control but pusshing the tab to the Accel side of the switch. The Set button does not work but the cruise activates and im not dead legging my rig for 35 hours. All the info i found in this thread was very informative thank you very much gents for sharing this information.
