Cruise Control

[veneto rs2]

I did connect mine as per picture, the photo it's probably from an normal 80 (could be B3..) but it did apply perfectly on both RS2 1995 and Cabriolet 1997




Stefano

[John B]

Hi Stefano,

Thanks for the guide earlier and the picture form the guide. The left hand drive is slightly different from the right hand drive version in this respect. Anyway, I now have a 12V connection through my blue/black wire. I can trace this to the cruise control stalk but CC does not work. I think it may be as you posted earlier, something to do with the contacts in the control stalk. Did you use IPA (Iso Propyl Alcohol) to soak the stalk?

Cheers

JB

[4WheelDrifter]

I did connect mine as per picture, the photo it's probably from an normal 80 (could be B3..) but it did apply perfectly on both RS2 1995 and Cabriolet 1997




Stefano

I am going to have to call a Scotchlok Alert!

[John B]

Finally I have my cruise control sorted.

The story so far was that I had: -

• tested the vacuum side for leaks.....all OK
• tested the vacuum pump and solenoid with 12v supply.....all OK
• tested 12V supply via fuse S12 with ignition on.....all OK
• tested 12V kicked in via fuse S29 when brake pressed (and brake light circuit initiated) ....all OK
• tested all the circuits for continuity......all OK

So the last two culprits had to be either the cruise control module or the cruise control stalk. I had read that Dmitri had seen some modules go faulty and so picked that first to dissect. So I carefully prised open the four crimped sections of the alloy body and eased the plastic black surround off then squeezed the alloy body to gently pull out the circuit board.

Here are the 3 pieces: -

tn_RS2 Mirrors and Cruise Control 028.JPG

... and here is the circuit board closer up : -

tn_RS2 Mirrors and Cruise Control 030.JPG

All looked OK. You can see the section where the board was dipped in varnish.

I tested the connectors to the circuit board....all OK

So I thought unless the module is fooked, the stalk was to blame.....more pictures and words tomorrow when I have time....

[John B]

So the stalk had to be taken apart to see if it was the culprit. Firstly I took the side of the stalk off that is closest to the dash board.

tn_RS2 Mirrors and Cruise Control 003.JPG

...and then the side facing the driver with the switch on

tn_RS2 Mirrors and Cruise Control 004.JPG

but be careful as there is a small roller to be aware of that this spring pushes on: -

tn_RS2 Mirrors and Cruise Control 005.JPG

[John B]

Then you ease the clip between the white stalk insert and the stalk body: -

tn_RS2 Mirrors and Cruise Control 006.JPG

and gently pull the white insert out whilst simultaneously feeding the wires in their black fabric wrap through the stalk from the hinge end.

tn_RS2 Mirrors and Cruise Control 007.JPG

[John B]

Then you can unclip the black "set" button cover to reveal two white inserts and 2 springs.....be careful they don't spring out and get lost.

tn_RS2 Mirrors and Cruise Control 008.JPG

[John B]

Push the white clip though the circuit board here: -

tn_RS2 Mirrors and Cruise Control 009.JPG

and pull out gently the white insert (effectively the on/off/reset switch) and circuit board: -

tn_RS2 Mirrors and Cruise Control 010.JPG

which you can then lift off to reveal the circuit board thus: -

tn_RS2 Mirrors and Cruise Control 011.JPG

[John B]

You can then clean the circuit board with isopropyl alcohol (IPA): -

tn_RS2 Mirrors and Cruise Control 012.JPG

and the circuit board should look like this: -

tn_RS2 Mirrors and Cruise Control 013.JPG

Now strictly you should replace a small amount of electrical grease on the copper contact surfaces but I did not do so.

[John B]

Rebuilding ....as they say is the reverse of what I did.

Next I did some electrical continuity testing and found that: -

• Off - had no response
• On - contacts 1-6 (12v supply to module) and 4-5 (brake light / clutch pedal depression to module) had connectivity
• Reset - contacts 2-4, 2-5 and 4-5 had connectivity
• Set - contacts 3-4 and 3-5 had connectivity

which matched the diagrams that I had.

In short I re-assembled the stalks and the steering wheel, went for a drive and had the satisfying click from the module, when I pressed the set button. All other functionality was tested OK. To do this I eliminated the vacuum switches by removing the pipe and inserting a bung (round pencil!). This is not unsafe as pressing the brake pedal still disengages the cruise electrically and in any case the stalk can still switch off the cruise. Once I had established electrical connections were working correctly I re-instated the vacuum switch pipe and checked that worked.

So my cruise problem appeared to be a stalk with dodgy contacts. HTH

JB

[John B]

.....or so i thought

When i got in the car at 0630 this morning and it was about +1 degree outside temperature, the control did not work.

However as the car warmed up it started to work, intermittently at first then all the time. It is strange that the control module is resting in the passenger footwell before being re-fixed and gets the benefit of the footwell heating. So i suspect the module is at fault and Dmitri's observations have affected me i.e. dry module joints. I cannot see them so i may have to get a back-up module but at least i know the wiring, vacuum and mechanical bits work

[John B]

Guess what? There's another issue. This story has got more twists than a Robert Harris novel (Enigma, Fatherland etc...for those who haven't heard of him) and I am going demented

For a little while the on-board computer that works out MPG and average MPG has "frozen" when the engine was cold, such that the last MPG reading when I switched the ignition off was statically displayed. This was the case tonight travelling from work and the cruise control did not work for over half an hour. As soon as the computer sprung into life.....yes you guessed it...so did the cruise. Maybe the dry joint is not in the module but in the dash from where the VSS signal comes and the crucial 12V supply from S12

[A80Avant]

I had this issue for a while now, where the cruise doesn't work when cold and only after a while. I actually thought it had to do with the hoses I jad used, potentially collapsing when vaccum was created so I replaced those with hard plastic hose instead. Now it does not work at all.

I also checked the plug of the switch and cleaned it. I haven't taken the stalk apart yet but I might give that a go as well.

When we wired the whole thing up we did use the white-blue cable from the dash and in my case the mpg never works as I use vems. However the cruise did work nicely for a long time without problems so I don't see how the dash computer has anything to do with it

Is there any way to check the pump if its functional or not?

[prj]

If the VSS signal going out from the speedo doesn't work the cruise control can't work as well, as that's where it gets it's VSS from...

[A80Avant]

If the dash is showing and counting kms as normal, is that a good enough indication that it works?

Also the same cable gets the signal for the rear lock different to turn off after 25km/h. If that still works then can I assume that the signal is still ok?