timing circuit

hello everyone...
i'm having a little problem and wondering if someone can help me solve it.
i wanna replace my car's alarm from cobra to clifford matrix rs2.1
my problem is that until now when i locked the car with the "cobra" all the windows in the car(including the sunroof)would close
i checked it out and there is a wire at the cobra which gives a 15 sec neg to the two "cobra" window roll up devices and to the sunroof(dont know how but when the sunroof wire is gettin a neg corrent it closes up.
so it means that the sunroof motor engages to close the sunroof even after the sunroof it closed for something like 7 seconds,and as i said after 15 sec the wire stops feeding the sunroof wire and the motor is disengaging.
now with the clifford i have a constant neg output,meaning that if i hook it up instead of the cobra's output the windows will be fine cause they has the roll up module that stop's feeding the windows motor when they closed b u t the sunroof's motor will not disengage cause the output from the clifford is constand.
what will eventually will burn the sunroof's motor.
my question is how i make the clifford's output last only 15 sec instead of being constant?
i dont wanna buy a part that does it cause i wont learn anything from it,so please try to explain me how can i do it myself.
and one last request:my output sould be as i said for 15 sec,if resistor/capacitor/both needed,please tell me what value they sould have to give me the requested 15 sec.
thanks a lot for your help.

https://peripheralelectronics.com/home.asp

please repost a cliff-note or check above link.



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Houston,TX
"The two most common elements in the universe are H+ and stupidity" (Ellison).