Adding cruise control to a 944 that didn't originally come with cruise
Posted: Tue May 10, 2022 7:32 am
Hi All, I am very excited to have successfully added cruise control to my non-cruise 944 Turbo!
Here's the video of the installation process:
https://youtu.be/cuDpkbvrrgA
Some of the process was a little tedious, but after having the finished product, it was SO worth it!
I sourced almost all of my parts off of ebay and the grand total came to just under $200. I got lucky and was able to get a couple of the items on best-offers which helped to keep the costs down a bit.
e-clip from menards: https://www.menards.com/main/hardware/f ... 54&ipos=32
support clamp from menards: https://www.menards.com/main/hardware/f ... 6&ipos=243
The clutch switch I bought and modified can be found here: https://www.amazon.com/dp/B000IYLKDE
You can take a small screwdriver and pop the clips on either side off and take the switch completely apart. I ended up measuring and marking where I needed to cut the body of the switch as well as the center plunger part. Also the switch has two sets of contacts (two that are for normally open configuration, and two that are for normally closed configuration) I ended up using the smaller set of connectors on this switch that are for normally open, which is a bit of a nomenclature because for the switch it is normally open, but on the car the clutch pedal holds the switch in and the only time it is normally open is when the clutch pedal is pressed in. when the clutch lever is released it closes the contacts of the switch.
Here are some pictures of where I cut it:
Some notes during installation:
1. After popping off the little rubber plug in the firewall for the servo cable to run thru, there was some foam padding there that the cable needs to go thru and it didn't want to go thru very easily, so I made a "sewing needle" out of a bamboo skewer and some string and attached that to the end of the cable and was able to pull the cable thru from under the dash.
2. Even though the throttle pedal rod is in the way for sliding that pivot arm onto the post, you don't need to remove the throttle arm, just press on the throttle pedal and that will move the arm out of the way enough to put that pivot lever on the post. Also, it is obviously less-than-ideal working under the dash but I found out that after sliding the pivot lever on I could get the e-clip onto that post easier than I though by using one of those locking pliers people use to grab fishing hooks when fish swallow them deep. I clamped the clip in the locking pliers and was able to get it onto the post quite easily.
3. Connect the servo cable to the pivot lever under the dash first, then connect the other end to the servo ball. I had to put the adjuster nuts at the full loose end of the threads (very similar to my car that does have cruise) and then I had to back the adjustment off on the throttle cable at the throttle body as well. When moving the servo linkage by hand it is very firm but was also like that on my car with cruise as well.
4. After I got all of the parts on the car, the cruise didn't work. I found out that it was because my clutch switch was mounted kind of sloppy and the clutch wasn't pressing the switch all the way when it was fully released. I could have saved a lot of time if I would have tested continuity across pins 7 and 8 on the top connector before plugging that connector onto the computer box. I ended up spinning that switch in the hole and it somehow snugged up and after that the cruise control worked properly.
I would like to give a big shout-out to edredas on youtube for help on questions I had about the wiring harness.
Thanks
Here's the video of the installation process:
https://youtu.be/cuDpkbvrrgA
Some of the process was a little tedious, but after having the finished product, it was SO worth it!
I sourced almost all of my parts off of ebay and the grand total came to just under $200. I got lucky and was able to get a couple of the items on best-offers which helped to keep the costs down a bit.
e-clip from menards: https://www.menards.com/main/hardware/f ... 54&ipos=32
support clamp from menards: https://www.menards.com/main/hardware/f ... 6&ipos=243
The clutch switch I bought and modified can be found here: https://www.amazon.com/dp/B000IYLKDE
You can take a small screwdriver and pop the clips on either side off and take the switch completely apart. I ended up measuring and marking where I needed to cut the body of the switch as well as the center plunger part. Also the switch has two sets of contacts (two that are for normally open configuration, and two that are for normally closed configuration) I ended up using the smaller set of connectors on this switch that are for normally open, which is a bit of a nomenclature because for the switch it is normally open, but on the car the clutch pedal holds the switch in and the only time it is normally open is when the clutch pedal is pressed in. when the clutch lever is released it closes the contacts of the switch.
Here are some pictures of where I cut it:
- switch1.jpg (722.58 KiB) Viewed 1158 times
- switch2.jpg (205.96 KiB) Viewed 1158 times
- switch3.jpg (395.06 KiB) Viewed 1158 times
- switch4.jpg (249.3 KiB) Viewed 1158 times
- switch5.jpg (288.73 KiB) Viewed 1158 times
Some notes during installation:
1. After popping off the little rubber plug in the firewall for the servo cable to run thru, there was some foam padding there that the cable needs to go thru and it didn't want to go thru very easily, so I made a "sewing needle" out of a bamboo skewer and some string and attached that to the end of the cable and was able to pull the cable thru from under the dash.
2. Even though the throttle pedal rod is in the way for sliding that pivot arm onto the post, you don't need to remove the throttle arm, just press on the throttle pedal and that will move the arm out of the way enough to put that pivot lever on the post. Also, it is obviously less-than-ideal working under the dash but I found out that after sliding the pivot lever on I could get the e-clip onto that post easier than I though by using one of those locking pliers people use to grab fishing hooks when fish swallow them deep. I clamped the clip in the locking pliers and was able to get it onto the post quite easily.
3. Connect the servo cable to the pivot lever under the dash first, then connect the other end to the servo ball. I had to put the adjuster nuts at the full loose end of the threads (very similar to my car that does have cruise) and then I had to back the adjustment off on the throttle cable at the throttle body as well. When moving the servo linkage by hand it is very firm but was also like that on my car with cruise as well.
4. After I got all of the parts on the car, the cruise didn't work. I found out that it was because my clutch switch was mounted kind of sloppy and the clutch wasn't pressing the switch all the way when it was fully released. I could have saved a lot of time if I would have tested continuity across pins 7 and 8 on the top connector before plugging that connector onto the computer box. I ended up spinning that switch in the hole and it somehow snugged up and after that the cruise control worked properly.
I would like to give a big shout-out to edredas on youtube for help on questions I had about the wiring harness.
Thanks
