Relay for Seat Belt Trans Lockout

HI All,

I was thinking about wiring up a relay so that in order to take the vehicle out of park and into drive you have to have your seat belt engaged (sensor in latch) and foot on the brake.  I was going to inturrupt the brake pedal interface that tells the trans lock that the person has thier foot on the brake (Ford Car) and tie it into the seat belt sensor.

1. have you ever heard of someone doing this

2. is the sensor in the seat belt latch, that basically just turns on a dash bulb, enought to trigger a relay?

3. see any problems to this?

Appreciate any feedback!

Other than its just NOT SAFE.....no, I don't see a problem with it....

WHY would anyone NEED to do this, I don't understand?

>  Other than its just NOT SAFE.....no, I don't see a problem with it....

Kar Tune, what exactly do you find not safe?  hooking into that seat belt circuit? Hooking into the gear lockout circuit?  Could you give me an example of what you are thinking?

>  WHY would anyone NEED to do this, I don't understand?

Maybe I should have explained that a little.  I am in the limousine business and we regularly have to leave the drivers seat with the car running in order to assit our customers.  I myself have a habit of manually locking my drivers door so no one could just hop in and go.  Other drivers are say less vigilant so I want to install something that is completely passive in terms of guarding from unauthorized use.  I figure a drunken frat boy thinking it would be a good joke to jump in and take off in a limo would not have the forethought to fasten his seat belt before driving off, thus giving us time to "correct" the situation.  Also a side benifit it would guarantee seat belt useage amoung our employees.  Also many in the tow industry have this same situation.  I have though about just a momnetary switch on the dash competing the brake interlock system (so would have to press the brake and button at the same time to get out of park) but the seat belt soloution seems more elegant.

Thanks for your input!!

Steve Walker - steve@capriceshop.com

" better yet tho, just put a hidden switch under the seat the completes the circle that the brake pedal creates to allow the car to come outta park. if you don't know the switch is there, you can never shift it outta park. "

Do you mean like an on/off switch or a momentary?  I want whatever I come up with to be completely passive, meanaing that when the driver gets out of the vehicle they do not have to do anything to "arm" the system.  When they put it in park it is locked so to speak. The disadvantage of this is that when our cars are at the car wash or mechanics we will have to stick around and explain to the attendants how to get it out of park, but I thought with the seat belt we could just get out of the car buckel the seat belt across the empty seat then the attendent will just sit on top of the seat belt for the little time he is in the vehicle moving it around.

I thought parents would like it also for new driver to get them in the habit of buckiling up. 

"don't know what would be unsafe about REQUIREING to put your seatbelt on to shift the car from park... but i'm sure he has a wieird off the wall reason. "

Well I hope Kartunes would respond about the safety issue, I think he may be more concerned about taping into that shift interlock system in the first place.  Thinking that if the relay went out now you cannot get it out of park and you are stranded.  But with Fords/Lincolns there is a way around the shift interlock feature, with GM's I am not sure.  So what ever relay I used it would have to be a very high quality and reliable one to prevent against being stranded somewhere.

"   you don't wanna have your hands off the wheel. think about it. push switch on the dash. one hand on the shifter, one on the button, one foot on the brake.   no hands on the wheel. "

Good point Maglin, another reason I like the seat belt route is you kind of do that before you start even engaging the controls of the vehicle.

" the same switch that runs your brake lights and 'shift from park' of the car, is logically the same switch. "

Thats what I am unsure about, I would think it would be a seperate curcuit for the interlock and brake lights but they may share the same switch down at the brake pedal.  I will have to get down there and start fishing around.

Thanks for the input Maglin!!