Cruise control troubleshooting
03-03-2007, 03:22 PM
#1
Instructor
Thread Starter
Cruise control troubleshooting
I recently bought a used but functional cruise control brain as in my 91 S2 I cannot set the cruise speed. The old unit used to accelerate but wouldn’t set. After installing the new one…it does nothing…not even accelerate!? The only thing that I can see is that the new brain is from 1985, whereas the one in the car is from 1990. Does that make a difference?
Syed
1991 S2
Syed
1991 S2
03-03-2007, 08:10 PM
#2
Three Wheelin'
Was it from a '85 or '85.5? Early and late cars have a different part # in PET for the computer so it might not work. You probably need to resolder the board in the original computer. That's what fixed mine.
Tom
'87 951
Tom
'87 951
03-03-2007, 08:51 PM
#3
its not the computer its the wiper arm in the servo. i had the same problem and fixed it. here ya go.
http://forums.pelicanparts.com/showt...cruise+control
http://forums.pelicanparts.com/showt...cruise+control
it worked just fine until about a month ago id engage the cruise control and it would just accelerate like mad. which is fun and all but not really what i was looking for. and really, i never take the car on the highway or for long trips but it bugged me that i knew it didnt work properly.
so clarks said to look at two things, the servo an computer board.
pulled the computer board, which to me, could have been Chinese, looked fine, nothing out of the ordinarily aside from the 8 million solder joints, all seemed okay... so i put that back.
next was the servo. Heres a small walk through:
Remove the unit from the car.
remove the nut that attaches the arm to the unit (13mm), and note the arms relation as well as the relation of the shaft to the housing. Remove the phillps screws, and you may need to pry the housing open a little with a flat head. Once you start to pull it apart….
There is a gear in there that is sprung, and its going to pop out, as long as you have a jewelers screw driver or a small pick its easy to retention it against the housing..
the order of assembly from the back to the front goes like this...
the "quarter gear” with the wipers on it, then the metal shaft that turns the arm, then the large gear, then the housing...
so i took all those gears out, and with a q-tip and contact cleaner wiped the tracks where the wiper arms "read". they werent unusually dirty but the q tip came up black until i went through about four of them... next using the same technique of q tips dipped in contact cleaner, i dabbed the contacts on the end of the wiper arms very carefully.
again, they were black and dirty but nothing seemed out of the ordinary, i cleaned them a few times with the contact cleaner....
then used some, and i mean a tiny bit, of grease on the end of a qtip and rolled just a little grease onto the plastic gears (same grease thats used on the sunroof gears).
Put everything back together...re installed it into the car...
Took the car out for a test drive, set the cruise and it WORKED! i couldnt believe my own eyes!
didnt cost me a dime!
so again, to the forums and clarks, a big THANKS here to the forum!
Kevin
i give the job "one wrench" and maybe just less than an hour of your time.
so clarks said to look at two things, the servo an computer board.
pulled the computer board, which to me, could have been Chinese, looked fine, nothing out of the ordinarily aside from the 8 million solder joints, all seemed okay... so i put that back.
next was the servo. Heres a small walk through:
Remove the unit from the car.
remove the nut that attaches the arm to the unit (13mm), and note the arms relation as well as the relation of the shaft to the housing. Remove the phillps screws, and you may need to pry the housing open a little with a flat head. Once you start to pull it apart….
There is a gear in there that is sprung, and its going to pop out, as long as you have a jewelers screw driver or a small pick its easy to retention it against the housing..
the order of assembly from the back to the front goes like this...
the "quarter gear” with the wipers on it, then the metal shaft that turns the arm, then the large gear, then the housing...
so i took all those gears out, and with a q-tip and contact cleaner wiped the tracks where the wiper arms "read". they werent unusually dirty but the q tip came up black until i went through about four of them... next using the same technique of q tips dipped in contact cleaner, i dabbed the contacts on the end of the wiper arms very carefully.
again, they were black and dirty but nothing seemed out of the ordinary, i cleaned them a few times with the contact cleaner....
then used some, and i mean a tiny bit, of grease on the end of a qtip and rolled just a little grease onto the plastic gears (same grease thats used on the sunroof gears).
Put everything back together...re installed it into the car...
Took the car out for a test drive, set the cruise and it WORKED! i couldnt believe my own eyes!
didnt cost me a dime!
so again, to the forums and clarks, a big THANKS here to the forum!
Kevin
i give the job "one wrench" and maybe just less than an hour of your time.
