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VT cruise Control not working after lights turned on

Legman_oz

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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

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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

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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.
 

accentstencil

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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

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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

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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

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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. :yeah:
 

Legman_oz

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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.
 
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