Fitting cruise control to a diesel

Hi,

I'm thinking of fitting cruise control to a 1995 P38a DT. I reckon i would need a console switch, new steering wheel and unlock of the function in the BeCM. I already have a high line BeCM, but i really don't know if the steering wheel control cables would already be in place. Have i forgotten something?

Cheers, Crt

The rotary coupler might not have the connections for the buttons on the wheel. You could always use the spare switch positions on the dash for Set and Resume to save changing the wheel.

Datatek, I've also considered this, as i don't find the steering wheel controls that attractive. Are the Set and Resume just push (push - on, release - off) buttons or are they something more complicated (as it is a custom with the P38 systems)? The diesel would only need the switch and some buttons, then?

I would think they are momentary switches allowing signal switching inputs to the BECM as apposed to true on/off switching. Although I maybe wrong....and willing stand to be corrected.

Cruise control on diesels is driven electronically by the ECM not the BECM. Although they interact. The resume button has no function on the diesel. With the correct wiring and components it maybe an easy task. What is or is not in the fitted loom could be the stumbling block.

wammers said:

Cruise control on diesels is driven electronically by the ECM not the BECM. Although they interact. The resume button has no function on the diesel. With the correct wiring and components it maybe an easy task. What is or is not in the fitted loom could be the stumbling block.

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I beg to differ, my resume button works and resumes set speed!

Keen to fit cruise to my lowly DT too - in fact it is the only option I really miss - is a cruise control ECU required with the diesel as well, or does the EDC unit do all the work? I would have thought the latter - maybe a trip to the RAVE wiring diagrams is in order!

chort - I for one would be really grateful to you for keeping us posted as you find out more, using this thread - I will do the same, although I am not actively pursuing CC on mine at the moment as I have more pressing things to do to the car (new airbags been sitting on shelf for a couple of months now...)

Cheers,

Jerry

Chrisfrain2007 said:

I beg to differ, my resume button works and resumes set speed!

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Wrongly worded on my part, the decellerate function is not on the diesel.

wammers said:

Wrongly worded on my part, the decellerate function is not on the diesel.

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How do you mean?

Chrisfrain2007 said:

How do you mean?

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On the diesel you have to touch the brake to disengage cruise to decellerate. Then you can use resume to go back to the preset speed. Pressing the button when cruise is engaged does nothing on the diesel. On the petrol you can disengage cruise by pressing resume/decell button to disengage cruise. Then when button is pressed a second time preset speed is regained. Only resume fuction on diesel not decell.

wammers said:

On the diesel you have to touch the brake to disengage cruise to decellerate. Then you can use resume to go back to the preset speed. Pressing the button when cruise is engaged does nothing on the diesel. On the petrol you can disengage cruise by pressing resume/decell button to disengage cruise. Then when button is pressed a second time preset speed is regained. Only resume fuction on diesel not decell.

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Got ya, yeah that's same on mine

chort said:

Datatek, I've also considered this, as i don't find the steering wheel controls that attractive. Are the Set and Resume just push (push - on, release - off) buttons or are they something more complicated (as it is a custom with the P38 systems)? The diesel would only need the switch and some buttons, then?

Click to expand...

They are just momentary contact push buttons, i.e. connect when pushed, disconnect when released. Set sets the current speed and will then increase the speed if repeatedly pressed or held. Resume is just that, press to resume the currently selected speed.

Thanks to all for the input, i'll dig into electrics in a week, when my main cruise control switch and nanocom are due to arrive. I suppose the wiring should be there, as until now i haven't encountered one bit of extras wiring missing on the car, all is there, just not connected. Quite weird for a plain cloth low spec'd DT.

Jerryltr, i too find this the only thing my DT really lacks. Ok, the trip computer would be nice, but not necessary (that's missing too), and maybe traction control i'll make sure to post any finds, and please others also do so..