VT cruise Control not working after lights turned on

[Legman_oz]

Hi all,

Im having an issue with my newly acquired vt, basically the long and short of it is that the cruise control works, until you turn the headlights on. Once they come on about 30 seconds later the cruise control turns off and you cannot turn it back on.

I have found that if you turn the car off and back on again you can use cruise control again.

Any help would be appreciated.

Thanks

[accentstencil]

Hi all,

Im having an issue with my newly acquired vt, basically the long and short of it is that the cruise control works, until you turn the headlights on. Once they come on about 30 seconds later the cruise control turns off and you cannot turn it back on.

I have found that if you turn the car off and back on again you can use cruise control again.

Any help would be appreciated.

Thanks

Check your brake and tail light globes, if one of the filaments has shorted and the brake light comes on when your lights are on, the cruise will disengage because it thinks the brakes are on. I hope this makes sense.

[Legman_oz]

Check your brake and tail light globes, if one of the filaments has shorted and the brake light comes on when your lights are on, the cruise will disengage because it thinks the brakes are on. I hope this makes sense.

but if it was the brake lights then wouldnt it do the same thing when i dont have my headlights on? im going to check the operation with the lights disconnected today so i will come back to you and let you know how it went.

[Ozzie]

Change the stalk.

Wear in the stalk is a very common problem for cars our age.
Especially the indicator stalk (which happens to be the cruise stalk)

[accentstencil]

but if it was the brake lights then wouldnt it do the same thing when i dont have my headlights on? im going to check the operation with the lights disconnected today so i will come back to you and let you know how it went.

There are 2 filaments in a brake/tail globe, one for the brake light and one for the parkers. If the filament for the parkers breaks and touches the filament for the brakes, in the right circumstances the brake light can come on when the lights are turned on.

[Legman_oz]

ok i have checked the globes - they all seem ok, but i did discover something new i can turn cruise control on and off whilst the lights are on, if the motor hasnt been started. I am off to buy some new globes anyway, just in case there is a short but i cant see it.

[Legman_oz]

Ok, updated info, it turns out i was a little hasty in my last entry, turning the lights on does turn the cruise control off, it just takes a few seconds for it to happen, and it doesnt matter if its the headlights or the parkers.

I have replaced the rear globes and the indicator stalk with brand new items, and still the same issue.

[accentstencil]

Does it cut out when you hit the brakes or just random? Since you have just bought this car maybe you are not too familiar with cruise control and are not aware that hitting the brakes turns the cruise off. Just in case you didn't know.

[Legman_oz]

no, i can have the cruise control turned on and active (with no parkers/headlights), and as soon as i turn the parkers/headlights on, the cruise control dis-engages and a few seconds later the cruise control turns off completely. i dont need to touch the brakes at all. If i turn the headlights off after this i cannot turn the cruise control back on unless you turn the car off and back on again.

Im no auto electrician, but i was thinking that maybe the issue could be related to a small power spike when you turn the lights on? i know its a similar thing with pc's that are subject to power spikes.

[accentstencil]

It's got me stumped. Good luck with it.

[WAGON MAN]

Do you have a trailer harness attached to the right hand rear tailight?

[Legman_oz]

Yes, there is a trailer harness, but i dont know exactly where it attaches to?

are you thinking that there might be a short in there?

[VTS5]

Do you have a trailer harness attached to the right hand rear tailight?

Dont mean to hijacking the thread,but i do have one connected to the r/h/r t/light and my c/c also not working (can turn it on tho)..

[WAGON MAN]

Sometimes the trailer harness can have a short or may not be wired properly if a non genuine harness is fitted.

Try disconnecting the trailer harness.

It is located at the RHR tailight or simply follow the trailer harness to where it plugs in.

Once disconnected test operation of the cruise control.

[Legman_oz]

Ok, i managed to solve the issue, it turns out that whoever installed the aftermarket lights (on the car when i bought it) screwed up the wiring of the globe holders, the mis-wired the active for the parkers to the common feed.

How they missed this in their testing is beyond me, as both filaments light up when you turn the lights on. I actually spotted it ages ago but thought i was dreaming it.....

Anyway, thank you to everyone who offered assistance to helping solve my dilemma

[accentstencil]

Glad you finally got it sorted out.

[Pommy09]

i have the same problem here when i turn my parkers on, i can't set my speed for cruise control. ive also happened to notice that when i break, my parkers come on, how do i check this out?