Mark42
Fleet Admiral
- Joined
- Oct 8, 2003
- Messages
- 9,334
I have a 1998 Pontiac Firebird with power pop up headlights. The design uses a control module to reverse the 12v dc motor to make the headlights go up or down.
There is an inherent problem with the design where a plastic gear in the motor assembly gets stripped out by the driving worm gear over time. Part of the flaw is that the motor is not turned off (either opening or closing) until a solid state control module detects the load created when the headlight housings reach their full open or closed position. This means that the motor is running right up to the point that the headlight housings hit their stops. I believe the shock load is putting undo stress on the plastic gear, making it wear.
To "lessen the blow" to the plastic gear, I was wondering if a resistor can be put across the motor poles to make it run slower. Not sure if the solid state module will read the load properly if this is done.
Thats what I'm asking you electronics wizards on the forum. How to reduce the impact on the motor gear to extend its life.
Here is a wire diagram of the motor control box (linked from Firebird Nation):
This link will take you to a forum where the above images can be viewed much larger for ease of reading:
http://www.firebirdnation.com/forums/index.php?showtopic=10304&st=0&p=91475&#entry91475
And a pic of the motor with gear box open just for reference:
There is an inherent problem with the design where a plastic gear in the motor assembly gets stripped out by the driving worm gear over time. Part of the flaw is that the motor is not turned off (either opening or closing) until a solid state control module detects the load created when the headlight housings reach their full open or closed position. This means that the motor is running right up to the point that the headlight housings hit their stops. I believe the shock load is putting undo stress on the plastic gear, making it wear.
To "lessen the blow" to the plastic gear, I was wondering if a resistor can be put across the motor poles to make it run slower. Not sure if the solid state module will read the load properly if this is done.
Thats what I'm asking you electronics wizards on the forum. How to reduce the impact on the motor gear to extend its life.
Here is a wire diagram of the motor control box (linked from Firebird Nation):


This link will take you to a forum where the above images can be viewed much larger for ease of reading:
http://www.firebirdnation.com/forums/index.php?showtopic=10304&st=0&p=91475&#entry91475
And a pic of the motor with gear box open just for reference: