Cruise Control Module removal.....??

[buckeyes1997]

Hey

I am trying to fix the cruise control on my 87 944. I have followed the directions on Clarks-Garage to clean the servo in the engine compartment but now I need to remove the electronics module that is above the hood release lever in the driver's side footwell. I have unplugged the 2 harnesses but how do I actually get the module off the holder? I cannot seem to find any bolts or screws holding it up there. How does one go about removing this module?


Thanks everyone
Matt

[EMBPilot]

What are the symptoms of your problems?
check this thread linked below.
the module is inside of a metal case. there are two or three bolts, one was tricky to get at if i can recall when removing the computer part.

however im not sure if you'll find much wrong with it there. i checked mine it was good, the problem was with the servo under the hood.

Cruise control FIXED! Kudos to you guys!

[buckeyes1997]

Thanks Kevin

Yes he basically did exactly what Clarks Garage suggested. I have done that as well with no improvement. Basically my cruise used to work and then it went intermittant and now it does nothing when i switch it on. I have cleaned/lubed/checked the servo in the engine compartment and now I want to resolder all the pads on the board but I cannot get the module off the side of the footwell. I really just want to know what the heck is holding this module in there....haha. I cant seem to see any bolts or fasteners holding it in there.

[Lexluther]

ok will the cruise control servo and computer from a 924s fit a late 944?

[earlr85944]

i have a servo and computer from an 86 944, $40 shipped

[JWest]

I just did this last week. The cruise would accelerate but not hold when set.

There are two 6mm (10mm wrench size) nuts holding the module in. One in front and one in back up above the box.

I did not see anything wrong, but I reflowed all the pads and now the CC works perfectly.

[EMBPilot]

Originally Posted by James Adams

...I reflowed all the pads...

What does that mean?

[Lexluther]

yeah, what is "flow pads"...? soldering the traces? or re-flowing the traces?

[EMBPilot]

im interested in what that means because after fixing mine a few seasons ago, it recently started to have the same symptoms again.

[Lexluther]

i am just curious cause my cruise accerates wildly

[rporzio]

I think that it has to do with the solder points on the board. Out of curiosity I Googled the term and learned that.

[JWest]

Originally Posted by EMBPilot

What does that mean?

I turned the circuit board with the parts (resistors/caps/ICs) facing down so I was looking at the traces and pads that the wires from the items on the other side poke through. Then I touched a soldering iron to each wire/pad until the solder remelted to give a fresh connection.

[EMBPilot]

Originally Posted by James Adams

I turned the circuit board with the parts (resistors/caps/ICs) facing down so I was looking at the traces and pads that the wires from the items on the other side poke through. Then I touched a soldering iron to each wire/pad until the solder remelted to give a fresh connection.

Thats it? that alone fixed your stuck acceleration problem?

[JWest]

Originally Posted by EMBPilot

Thats it? that alone fixed your stuck acceleration problem?

Yep - it all works as-designed now.

[Todd Staples]

I had the same problem. Cleaned up the servo and still didn't work. Checked out the computer, soldered the only place that looked suspicous. Still no go. Mine was intermittant also, then quit working all together. I replace the servo and computer that were both working on the donor car, but it failed to fix the problem. Could it possibly be in the activation switch on the steering wheel?

[rporzio]

Let's get some discussion going on that switch located at the wheel. My 84 is having some issues and that's where I was going to look next.

[dr_dave]

Originally Posted by JWest

Yep - it all works as-designed now.

Hi all. I recently saw a YT vid where the owner planned to "reflow" (heat the solder until it melts then remove the heat so the liquid solder will again flow around the component lead). Why would you need to reflow? Because the Cruise Computer is subject to vibrations and swings in environmental parameters. The soldered connections on a circuit board are called 'joints'. This is where electronic component wire leads are connected to the tiny wire patterns (traces) on the circuit board. These joints are often very small and thus somewhat fragile. With 40+ years of flexing these tiny metal connections develop minuscule cracks which can enlarge to the point where a component wire can actually lose contact with the associated circuit board trace! The component then becomes disconnected, at first intermittently, then years later it can become completely disconnected. This deterioration of the solder joints is a random event, you never know which component is the problem. So the owner of an older Porsche should try to rejuvenate all of the solder joints on an aging circuit board.

Reheating the solder 'joints' to the point of reflow may correct the bad connections as good as new, so the circuit once again works. Worth a try for sure, considering the cost of a new or reconditioned circuit board. Question becomes your Method - buy a very small electronics soldering pencil, practice soldering for a while on a 'practice board', watch a few YT tutorials and then reflow several hundred connections one at a time (you will need a Very Steady hand) and good soldering technique or Plan B - use a heat gun designed for electronics use (heat shrink tubing, reflowing solder joints en masse). Again practice on some junk board 1) adjust the heat setting to MED to start, then similar to blowing leaves, sweep the hot air over the entire non-component side of the board. 2) Keep the gun 3-4 inches away at all times. 3) Keep the gun moving always. Too much concentrated heat can/will damage or melt certain components, so heat only the underside of the board where most solder joints are. Carefully observe the solder joints as you heat them, as the solder joints approach their melting point (185F) they will start to shine like polished chrome. At that moment is it time to move the heat gun to another area or remove it. The super shiny solder will reflow around their associated wires healing any poor connections. Do NOT reheat solder joints once they have been reflowed once - each reheat cycle burns off any (good) flux and the solder joint often get worse rather than better.

Note that very often automotive circuit boards are conformally coated (see Wikipedia).This coating can dramatically interfere with reflowing solder joints successfully.
Note: People who wish to build / repair electronics for the US Government / Military usually go to Solder School for an intensive 3-4 day training. Annual Recertification classes are also required..

-drs BSEE, MSEE


He started with a soldering iron, then reasoned that it may be safer

[kdjones2000]

Why on earth did you resurrect a 2 DECADE old thread for this drivel?

[Monkey Wrench]

I wonder how many have removed or disconnected the thing. It doesn't seem very reliable or necessary. any time Ive actually used one I find myself frustratrd because my car wants to drive alongside another car. normally Ill just naturally avoid that unless traffic conditions don't permit it. Basic defensive driving habits.

Maybe its nice if one does long drives across praries, deserts etc.

[originalowner]

I hate not having cruise control. I even carry a spare module. If I end up beside someone for too long, a little pressure with the right foot easily solves that.