Technical Cruise Control

[glowplug]

I finished fitting my cruise control today and must say am very pleased with the result. My car is a 2003 ELX JTD 115

I bought an AP900 system from BridgeWater electronics but the same system can be had form a good many other traders. It comes in a nice kit however the supposed "Plug and Play" T connector that is meant to T into the Accelerator Position Sensor and the ECU harness is incorrect certainly for the 98-2004 models. It may well be right for the facelift models but neither the supplier nor the manufacturer could confirm this. As such, not wanting to cut the original car wires to manually bride in the system I made my own harness. I managed to get a second hand sensor along with both plugs from a breakers, cut off the sensor and just used the plugs. I cut off the plugs from the supplied harness and replaced them with the second hand ones.

Now to create the harness you need to know what the signals coming to and from the ECU are. As I mentioned in a previous post the documentation in the DTE and the E-Learn is seriously misleading. The pinouts shown on the plugs are wrong and the colour codings given are in Italian even though the body of the text is in english. If you are to undertake this this you must do some serious due diligence before starting the job.

Tips

The plug config from the ECU to the TPS has 6 pins and they are number (looking from the back of the plug where the wires come in

2----------1
6 5 4 3

Pinouts are

1 = Signal
2 = +VE
3 = -VE
4 = Signal
5 = +VE
6 = -VE

The TPS has 2 x potentiometers a primary and a back up. Pins 1,2,3 are for the primary and 4,5,6 the secondary

Once you have have created the harness the rest is straight forward and just follow the instructions. Brown and White to brake switch, purple to clutch switch and green to earth.

You need to connect the system to speed sensor and RPM sensor. I took these from the back of the speedo cluster. On mine there are two plugs a smaller black one and a larger grey one. The grey one is Plug A and pin 5 (Brown/Yellow) is VSS (goes to Blue on the CC) whilst pin 6 is RPM (White) (goes to Yellow on the CC)

Once down you have to do some electronic systems setting to tell it to recognise the brake pedal, throttle position and speed settings. Done !!

 

[N&J]

Sounds interesting - but complex! I'm interested in what physical controls are supplied. Where does the switch go and how is it set/ operated?

Nick

 

[glowplug]

There are a choice of controls but by default a traditional stalk is provided.i will upload a photo to show. You need to e comfortable with electronics and a soldering iron to take on the job

 

[DiamondDave]

Sounds great, thanks for the info.
I would certainly like to look into this when I have the turbo rebuilt and am back on the road.
What kind of money are we talking?????

 

[glowplug]

Ah yes, well this is the point where it may cease to seem appealing. The kit itself was 288 all in including postage. However I then had to purchase the plugs, which of course the breakers would not separate from the sensor so another 25. I could have gotten them cheaper off a privateer who was breaking his Multipla but for some reason he seemed incapable of finding the plugs.

That said you do NOT have to make your own loom, you can simply cut the plugs off the one supplied and break them into your existing sensor wiring. I just chose not to because I like the neater option of being able to remove the system cleanly as and when I sell the car. Also if you have the newer shape the supplied T Harness may simply fit. If you do look at the plug that connects your TPS to the ECU loom. You should find it up behind the clutch pedal or in that vicinity. If not just find the back of the TPS and follow the cable from there till you find it. If the plug is rectangular and white then you will need to create your own. If however it is longitudinal and black (similar to the plug that goes into your MAF) then the supplied one will work fine.

Now you may ask why I chose to spend almost 1/2 of what the car is worth. I have a bad hip and do a lot of mileage due to my job. These two factors make normal driving painful for me without CC. My old Chrysler Voyager had factory fit CC and so too does my replacement SEAT Alhambra but as the wife generally has to cart my kids and their friends around she needed the extra seat the SEAT provides. Now that I have figured I might as well keep the FIAT until the wheels fall off fitting CC was the obvious addition.

 

[DiamondDave]

Ya, that's €400.
Unless my motorway driving increases i'll be spending that on tyres instead.
I had CC on my 147 which I used all the time, even on the back roads.
Can't see why such CC is is so expensive any more.
Once developed, the electronics shouldn't be that expensive to produce.
I'll just have to wait until there are cheap rip-offs on ebay.
I saw a Polish post somewhere describing the electronics of how to make your own.
Can't remember where it was.
Would you trust it?!?!?!?!?

 

[glowplug]

I promised to upload a picture of the CC control stalk. Hopefully I have attached this image correctly

 

[guizzo]

I had cruise control put in my jtd multipla in 2008 shortly after buying the car, I can do almost any mechanical job but electrics is my weak point so I had it fitted at the price of £400 total and it's been money well spent, I don't think it's expensive if you compare it to some sound systems that people by, I've still got the car now and I've had to do some work for the MOT and yesterday there's a fault with the alternator, so that will keep me busy for a while.

 

[Uzi22]

I finished fitting my cruise control today and must say am very pleased with the result. My car is a 2003 ELX JTD 115

I bought an AP900 system from BridgeWater electronics but the same system can be had form a good many other traders. It comes in a nice kit however the supposed "Plug and Play" T connector that is meant to T into the Accelerator Position Sensor and the ECU harness is incorrect certainly for the 98-2004 models. It may well be right for the facelift models but neither the supplier nor the manufacturer could confirm this. As such, not wanting to cut the original car wires to manually bride in the system I made my own harness. I managed to get a second hand sensor along with both plugs from a breakers, cut off the sensor and just used the plugs. I cut off the plugs from the supplied harness and replaced them with the second hand ones.

Now to create the harness you need to know what the signals coming to and from the ECU are. As I mentioned in a previous post the documentation in the DTE and the E-Learn is seriously misleading. The pinouts shown on the plugs are wrong and the colour codings given are in Italian even though the body of the text is in english. If you are to undertake this this you must do some serious due diligence before starting the job.

Tips

The plug config from the ECU to the TPS has 6 pins and they are number (looking from the back of the plug where the wires come in

2----------1
6 5 4 3

Pinouts are

1 = Signal
2 = +VE
3 = -VE
4 = Signal
5 = +VE
6 = -VE

The TPS has 2 x potentiometers a primary and a back up. Pins 1,2,3 are for the primary and 4,5,6 the secondary

Once you have have created the harness the rest is straight forward and just follow the instructions. Brown and White to brake switch, purple to clutch switch and green to earth.

You need to connect the system to speed sensor and RPM sensor. I took these from the back of the speedo cluster. On mine there are two plugs a smaller black one and a larger grey one. The grey one is Plug A and pin 5 (Brown/Yellow) is VSS (goes to Blue on the CC) whilst pin 6 is RPM (White) (goes to Yellow on the CC)

Once down you have to do some electronic systems setting to tell it to recognise the brake pedal, throttle position and speed settings. Done !!

Hi, and thank you again for the great explanation.
I understand you've sold the car some time ago, but I’d appreciate your help if you’re able. I have a second series model, and unfortunately, being RHD, it still uses the same potentiometer as the first series. On LHD models, they updated the pedal, but not on ours.

When I purchased the cruise control kit, they provided the harness for the newer (LHD) pedal, so I had to source the older-style white connectors, just like you did, to adapt the harness.

Your description above is helpful, but I was wondering if you have a photo of how you wired the harness with the new connectors. Examining the harness I received, I can see that three of the wires appear to connect the two black connectors directly, creating a stable line without passing through the cruise control module. The other three spots on each connector connect to the module using the 5 wires coming out of the CC. On one side, you have red, brown and green, while on the other, white, yellow, and green, with the green appearing to be split into two, feeding into both connectors.

Based on the documentation from the manufacturer and examining the provided harness, I also understand that one of the two lines (Signal, VE+, and VE-) must be connected directly, for example, with 123 pinouts on each connector, to create a continuous loop that bypasses the cruise control module. This is how the signal is passed through natively.

That would leave the other 6 pinouts (3 on each connector) to allocate the remaining wires, Signal, VE+, and VE-, to interface with the cruise control. From the harness layout, it appears that the brown/yellow wires are intended for the low signal (which I assume corresponds to VE− on both connectors), while the red/white wires are designated for the high signal (VE+). That makes sense as a parallel tap into the pedal’s output.

However, the one point I’m stuck on is the Signal wire. From what I can see, it would logically connect to the two green wires in the harness. But the issue is that, according to the manufacturer’s documentation, the green wire appears to be a ground. And as it stands, there’s no wire available in the harness that seems to intercept or carry the actual Signal line from the pedal, which is confusing. Additionally, on the wiring diagram for the Cruise control, there are 5 wires, and I'm unsure why the green wire is split into two on the T harness.
If you have any clarity on this—or a photo showing how you arranged the connections—it would be massively helpful. Thanks again for your time and help!

I’m trying to figure out exactly how to connect everything to the new connectors and would appreciate any visual references or further clarification you might have. I've also attached a few pics for your reference. Thanks a lot for any input you would be able to provide.