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87 turbo when I start the car the cruise servo has a clicking sound. THe only way to stop it is to disconnect the pin plug. AFter reading what seemed like a 100+ threads on CC in some of these threads fellow rennlister's have described the same problem I am having but I have not come across a diagnosis or a solution for this problem. Help
I too have had this problem in the past, and from what I found out from speaking to others is that the cruise brain is likely faulty. It apparently is sending signals to the servo and causing it to malfunction. Like you, I simply disconnected the plugs and this "solved" the issue until I could address it. I had my cruise brain rebuilt and after I put it in, the clicking was gone but I still have the same original issue - the cruise did not work. I am in the process of trying to track down the current issue, but I think it may have something to do with the cable connection to the arm on the servo. I am thinking that the arm is not where it should be and maybe it does not pull the cable as it should, so I am going to tighten the cable connection to the arm. (When I manually move the arm with the cable attached, it does easily move the throttle plate so that seems positive.) Hope that will fix it, but not really sure. At any rate, having the brain fixed DID stop the ticking sound at the servo, so I take some comfort in that at least.....
As an aside, I am continually befuddled by the connectors here - it's hard to see the pins as you try to connect these and I'm really not sure if I am getting all in correctly or what..... I think I am, but really not sure.
You can do some testing on the servo motors. Below are my readings and what the service manual lists. After getting my control unit repaired it works flawlessly now.Resistance measurements on the multiple-pin drive plug:
Open the cruise control brain box and look at solder joints and copper traces. I bet there are some, if not many, bad joints and a few areas where the copper tracing is pulling away from the board.
I have a somewhat similar issue but haven't been able to figure out what it is.
The servo motor would lose its mind from time to time. Would just jump around on its own and the only way to stop it was to turn off the car or unplug it. CC would engage but only accelerate. Re-soldering the board made the CC work properly, but the servo still would lose its mind.
Bought another servo out of a low car, but the issue is still there.
Haven't put a bunch of time into it since I don't need the cruse control, but would be nice to have it working properly.
I had the same issue with my '90 cabrio, kinda of like a machine gun (perhaps slower) behind the glove box sound.. The only thing that cured it was to swap in a different, known good CC brain-box (located above driver left foot). It also cured the "infinite accelerate". I had thought it was the anti-lock valves firing off, and spent time trouble shooting that until one day I had the car running with the hood open and the clicking started coming from the CC servo. Swapping in a known-good servo did not help. So in the end, it was a good CC brain box.
Yeah, that is what mine is doing as well. Sad thing is the module works to some extent, but even after re-soldering everything the "machine gun" nature still persists. CC engages as it should.
Wasn't there a 911 module that was compatible with our cars and folks had better luck with those than the 944 ones? I can't remember which years of 911 worked..
Most likely some of the electrical parts on the control unit's board are bad & need replacing. That was the issue with my original unit. I also had luck with a used one from a 968. They are date coded so you can tell which modules are a later build & may have been better quality as the line progressed.
07-23-2009, 12:45 AM
another cruise control question
