Cruise Control not working

grandnat_6

New Member
My cruise control never worked since I bought the car and want to get it going. Is it usually the turn signal stock the reason for the cruise not working? When you turn it on it does not light up the cruise light on the dash.

If that's the first thing to replace, what would be the next likely culprit?

Thanks,

Jim
 

KC87

Well-Known Member
Go under the dash and make sure the CC switch that rest against the brake pedal "like the brake switch
does" is getting pushed all the way in or the CC won't activate. When you press on the brake the button
comes out to shut it off.
 

Blaine87

New Member
I am a new member, but have found this test on line to help with checking cruise issues. Hope it helps. I am still having issues of my own yet.
 

Attachments

  • cruise control 87 GN.pdf
    2.9 MB · Views: 65

grandnat_6

New Member
Started to work on the cruise control tonight. Thank you for the information Blaine87. I am a little stumped going thru the checks. Test one passed. Test two did not. I'm not getting any battery voltage between pins A&J in the test chart. Going to Fix B; it says to pull the wire connector C235 and check terminal A for power. The diagram is a bit hard to read. I'm assuming its the connector coming from the 5 amp cruise fuse. Which is the C235 connector in this picture?

image0.jpeg
image1.jpeg
image2.jpeg

Also, What is the big black box hanging down in the second picture and is there somewhere it should be clipped to like the cruise control module? And again, in the third picture; in the lower left hand corner. What is this connector for? The plug is black and the socket is white with duck tape over it. I doubt this came this way from the factory?

A note; my cruise control light does not light up on the dash if I turn the stalk switch to "on". I did check and ohm the 5 amp fuse. I do have power where the fuse plugs into the terminal block. Pin J is grounded.

Thanks.
 

1986 Buick GX1

GX1 #001 [The One and Only]
Started to work on the cruise control tonight. Thank you for the information Blaine87. I am a little stumped going thru the checks. Test one passed. Test two did not. I'm not getting any battery voltage between pins A&J in the test chart. Going to Fix B; it says to pull the wire connector C235 and check terminal A for power. The diagram is a bit hard to read. I'm assuming its the connector coming from the 5 amp cruise fuse. Which is the C235 connector in this picture?

View attachment 385923 View attachment 385924 View attachment 385925
Also, What is the big black box hanging down in the second picture and is there somewhere it should be clipped to like the cruise control module? And again, in the third picture; in the lower left hand corner. What is this connector for? The plug is black and the socket is white with duck tape over it. I doubt this came this way from the factory?

A note; my cruise control light does not light up on the dash if I turn the stalk switch to "on". I did check and ohm the 5 amp fuse. I do have power where the fuse plugs into the terminal block. Pin J is grounded.

Thanks.

The cruise light in the dash only comes on when the cruise control is active.
When driving turn the stalk switch on, press the set button then the dash light comes on.
Not like these new dumb cars where you don’t know if you’re in cruise mode even though the dash light is on. Lol
I’ve slowed down behind someone, passed them, saw the dash light on and let off the gas. The next thing I know I’m doing 35 in a 55 and the guy I just passed is laying on his horn for me to speed up. Dumb!!
 

grandnat_6

New Member
I know. I did that and it does not come on. I found an easier to read diagram. I think my C235 connector is the flat 4 wire connector in the last picture in the center off to the left. I'll check it out and continue tonight. I thought It was going to be a single wire but it's not.
 

salvageV6

Daily Driver
Read Pin A to any good ground point not using Pin J. If you don't read 12 volts on A check the Cruise Fuse and Stalk ON switch. C235 comes out of the steering column from the stalk, it's a flat blade type connector on flat phone cord style wiring so its easier to fish down the steering column. Pin J should be a good ground you can check that with an Ohmmeter to a good ground point like the battery.
20220805_130423.jpg
 

salvageV6

Daily Driver
Cut the connector end off the old one and tie a nylon pull string to the wire and fish it up through the column when removing the old stalk so it's in place to gently pull the new cable down through the column. The new one will be a bit of work to pull through the column due the connector but if you tie the string to the wire portion just above the connector with a good electrical tape such as Scotch 33+ it should work out well. A coat hanger or ceiling tile support hanger bendable aluminum rod will work well as will a 1/8" thin steel wiring snake should you pull the pull string off the new wire by mistake and have to re-snake it.
 

grandnat_6

New Member
Installed the new multi switch/stalk tonight. 5 minute job with a piece of string. Took it out after for a test. They system works now. But when I push the set switch it likes to accelerate HARD. Took it out on a back road and hit the set button again and the car kept accelerating and got up to 60 miles an hour so I shut it off. After looking back at the wiring diagram. I want to say the electrical part should be working good, but now I might have a vacuum leak? Anyone have this happen or have any good suggestions on where to look next? Thanks!
 

grandnat_6

New Member
Worked some more on the cruise control tonight. Checked the vacuum lines. They are deteriorating have 36 yrs for sure. I don't have anything for vacuum and used an old hand ball pump to check the lines. Pulled the small line from the check valve to the cruise control servo and found where the line meets up with the end of the nipple was cracked. Not sure if it always was this way or if it was due to me twisting and pulling to remove it. Cut it off at that point and slipped it back on. Also removed the end that goes into the servo. Pumped some air into there as well. Checked on the vacuum reservoir tank and line as well. Seems all good except for being old. Put it all back together and took it for a ride and tried the set button on the cruise control switch. Again it started to accelerate hard but then stopped. Tapped the brake and it stopped. Played with it some more and each time it got better. It got to the point were it would hold speed better but was a bit jerky accelerating and then letting off. I'm thinking for the 25 + years it sat not working that the servo must be a little sticky and maybe I should take it apart and clean it up with some electric motor cleaner or something as I'm sure there are some moving parts in there. Anyone ever do this before and have some tips? Thanks.
 
Top