Cruise Control Gremlin

[discoveraus]

My cruise control is playing up and driving me nuts. When selected it works fine until I touch the brake pedal to slow down, it then locks out until the engine is stopped and restarted.

Using the RES switch or the Dashboard Control switch to turn it off  works correctly every time. Trouble is other road users on the freeway do things where I need to slow down now and not in 10 seconds so the brakes often get touched.

This is my 3rd ECU in 12 months, original, rechipped and a warranty replacement of the rechip. Both the original ECU and warranty replacement had (have) the problem. It cannot be peculiar to my truck.

Thanks in advance for any ideas

[dm_td5]

It sounds like a switch problem to me.  It could be a bad contact in the steering column, a faulty bake switch or the accelerator itself.  Check the type of accelerator as to whether its a 2 or 3 pot unit (I think that's right, I'm working from memory).  Older ones were different to newer D2's and the ECU needs to know this.

Sounds strange, also any fault in the brake system will knock out the cruise control, so check the brakes out - if you have a trailer plug check it for any issues.

[discoveraus]

Hello dm_td5,

Thanks for the tips, I do have a trailer plug with an electric brake controller fitted. The controller picks up its brake signal from the RHS rear brake light wiring so it should be separated from the ECU inputs.

I will check out the other items, your memory is OK, TD5's do have either  a 2 pot or 3 pot accelerator pedal. I dont know when they changed but will chase these out also.

regards

Discoveraus

[discoveraus]

Hello all,

Happy new year.

Further to my previous post on this topic I have investigated everything I can think of and have found no faults or wiring errors to cause my problem with Cruise control but I have found , to my surprise,
that everything works fine when the caravan is connected and the electric brake unit is loaded up by the caravan brake magnets.

This leads me to suspect that I am getting a voltage spike from the brake controller and that this is affecting the cruise control. The magnets are connected to the output of the controller so the spike must be on the output wiring of the controller.

I plan to build a small capacitor surge diverter and connect it to the brake controller output terminals to see whether I can overcome the problem and will probably also install a surge diverter onto the inputs as well.

regards

Discoveraus

[Winaje]

Thanks for the update, looking forward to hearing what you find...