911 sc cruise control

[CraigT]

can anyone tell me the best way to trouble shoot my cruise control. just bought 83 SC and i am working my way through the little things that don't work. could really use some advice on how to check my cruise control. thanks Craig

[unclebilly]

Best is to just remove it... just adds unnecessary weight.

If it really needs to stay, check for vacuum leaks.

[rusnak]

I have a slight surge in my cruise control. Not total failure, just a surge of about 500 rpm every 5 seconds. I'm hoping that the module is ok since they cost about $600 or so new. I'm going to start by pulling a vacuum on the cruise control football thing in the engine compartment and see what happens. I've already checked the hoses and clamps. Next I'm going to pull the module and look for broken solder connections. If that fails, then I guess I've got to find a troubleshooting manual or look for a good module testing and rebuild service.

[wilke3169]

Bentleys has a very good trouble-shooting sequence. Mine doesn't work and I wish it did.

[tcar]

Do the Bentley troubleshoot. If you don't have a Bentley, Pelican sells them. Get Wayne's 101 Projects book while you're there.

There are a number folks on here, that when someone posts that something doesn't work, or work correctly, they just "Remove it".

Some of us want to keep things like A/C and cruise, and enjoy troubleshooting and fixing. If it turns out to be the computer, you can get them on Pelican 911 used parts thread from time to time. I found a good one on ebay also.

[schoward]

Get a little multimeter from pep boys and do the bentley procedure. You will need a helper to hit the brakes, etc while you check readings. Easy novice project.

I resurrected the cruise on my 81. Many of the 'brain' modules have not stood the test of time. If yours is bad, there is a company called GDL that rebuilds them for something like $250. In my opinion, I say dont be tempted to buy a used one. It is a good chance that used ones will have quirks as well with their age. I once got a used one that worked fine when moderate temps but when cold out it would set speed then mash the pedal to the floor a few mins later.

[RSBob]

Cruise Control Fix from Mr Click Click...

[jeffbottman]

Originally Posted by RSBob

Cruise Control Fix from Mr Click Click...

Even before doing the Bentley's procedure, you should replace the (2) electolytic caps in the above link. Also, reflow all the solder joints on the board. Both of these things are pretty easy to do with a soldering iron, flux, and solder. You do need to remove the encapsulation layer to do the reflowing, and I found paint stripper works pretty well; don't get it on the top of the board though.

IMHO, this work should be done for preventive purposes even if it's not currently needed.

In my case, and for lots of others, this is all it took to fix the cruise control.

[triplenet]

I think that is a common issue on SC's.
Our 82 would slowly loose speed. I had it fixed once, but it reappeared.
My solution was to forget about it.

[Nick Triesch]

My CC would lose speed. I found a used module on eBay, installed it and now it works great. For a couple of years now. I read that the module gets beat up from driving after 25-30 years. Fixed now! BTW, I found mine for $65.00.