3.2 Carrera Cruise Control not engaging

[KM 1989 Cab]

Good day!
I am having trouble diagnosing and finding a potential solution with my Cruise Control no longer engaging on my 1989 Carrera Cabriolet. I would appreciate any support and guidance from this forum. I am new and look forward to learning from this group.

[Nick Triesch]

I fixed my speed control by doing a search on eBay and found the little silver computer that is easily changed out way up front in frunk . I found a rebuilt unit. Under $100. I think the same unit was used on other European cars. Works perfect.

[Lammers]

Fixed mine yesterday, the clutch switch has a little lever that comes out and it needs to be engaged when your foot is off the clutch. The lever is made from soft metal and I just had to bend it upwards for it to be in the correct position. To test, check for continuity between the cruise control fuse and pole number 85 on the relay. you should see a change when you press the clutch.

[WMichelsen]

Lammers post above is a great cheap first check. Otherwise:

Over the years, I've had 3 of the CC brain units fail (original and 2 used replacements). They either failed straight up, or would fail to hold speed then eventually fail completely. I understand some capacitors on the board, or poor solder joints, are common causes.

This time, I intend to use one of the CC rebuild services. I've come across this one: cruisecontrolrepair.com. There may be others ??

[mysocal911]

Originally Posted by KM 1989 Cab

Good day!
I am having trouble diagnosing and finding a potential solution with my Cruise Control no longer engaging on my 1989 Carrera Cabriolet. I would appreciate any support and guidance from this forum. I am new and look forward to learning from this group.

The '88 and later 3.2 CC rarely fail!

[KM 1989 Cab]

Originally Posted by Lammers

Fixed mine yesterday, the clutch switch has a little lever that comes out and it needs to be engaged when your foot is off the clutch. The lever is made from soft metal and I just had to bend it upwards for it to be in the correct position. To test, check for continuity between the cruise control fuse and pole number 85 on the relay. you should see a change when you press the clutch.

Did you have to remove the switch completely to bend the soft metal upwards?

[rokemester]

There are many good CC threads on this tech forum. I have an 87 Targa and I had my brain box rebuilt. Everything AOK after that.

[mysocal911]

Originally Posted by rokemester

There are many good CC threads on this tech forum. I have an 87 Targa and I had my brain box rebuilt. Everything AOK after that.

The '87 and earlier are more likely to fail than the '88/'89 units.

[Lammers]

Originally Posted by KM 1989 Cab

Did you have to remove the switch completely to bend the soft metal upwards?

Nope, I was able to reach in with my finger and bend it upwards, the metal is soft and it’s probably why it got bent out of position in the first place. I did remove the gas pedal and back plate.

[Lammers]

Here’s a picture where you can see that the metal lever is bent downwards and not making contact with the clutch lever.

[KM 1989 Cab]

Originally Posted by Lammers

Here’s a picture where you can see that the metal lever is bent downwards and not making contact with the clutch lever.

Thank you so much for the clear direction and follow up. Just completed and now buttoning up the driver footwell to road test. I do have another question for you based upon other posts and testing the #85 pin on the D or #4 relay. Do you have a pic referencing the #85 pin to electrically test the clutch switch with a voltage meter?

[Lammers]

Originally Posted by KM 1989 Cab

Thank you so much for the clear direction and follow up. Just completed and now buttoning up the driver footwell to road test. I do have another question for you based upon other posts and testing the #85 pin on the D or #4 relay. Do you have a pic referencing the #85 pin to electrically test the clutch switch with a voltage meter?

If you’re looking for a specific reading, I don’t have a pic. It would be dependent on whether I measure before or after the fuse anyway . I just looked for a fluctuating when I pressed the clutch, I achieved some and that was enough.

[mysocal911]

Originally Posted by KM 1989 Cab

Thank you so much for the clear direction and follow up. Just completed and now buttoning up the driver footwell to road test. I do have another question for you based upon other posts and testing the #85 pin on the D or #4 relay. Do you have a pic referencing the #85 pin to electrically test the clutch switch with a voltage meter?

It's a simple test just using the ohms function of the VOM!