In my quest to enhance the Cougar, I opted to tackle the electric motor headlight conversion. One thing that I was not too crazy about was the speed at which the headlight door opens and closes on the existing kits. I wanted to slow that movement, and found that I could use a PWM to accomplish this. I have a buddy who is in the retrofit lighting business, so with his guidance, we were able to wire this in. We were able to rig the PWM to pulsate the voltage on the negative feed being supplied to the motor, thereby slowing the movement.
Video link near the end of the post
The motor bracket build was pretty similar to what is currently out there, so I really won’t go into the details of how it was done.
Some differences: I used a heim joint on both ends of the motor arm which allowed for two way adjustment. The motors are from a 90s Miata.
Here is a video comparing the speed without and then with the PWM for comparison. The synchronization between the doors are off by just a hair, but this is due to the arm adjustment that I need to make on the driver side.
Yea, the kits out there are pretty pricey, although I guess it’s justified in a sense.
With the motors, hardware, metal and all other electrical components I probably spent around $300. Fabricating the brackets, and motor pivot arm took a lot of time. Even with a drill press, bench grinder, welder and a range of other industrial tools at my disposal, I spent a great deal of time measuring, planning, rough cutting, recutting, test fitting, cutting…you get the picture. If you have the tools and time, go for it, but I can understand how some would rather spend that money to get the kit.
Be careful of the little, cheap PWMs out there, you need the quality ones rated above 30 amp.
You are correct, you do have to justify what your time costs as well. Time is money as they say but sometimes its fun just to build something too if you have the means. My issue ends up being time, I have the tools but time is hard to come by sometimes. The nice thing with headlights is its not a critical thing(can open manually) so its something that can be worked on little at a time.
Thanks for the tip on the PWM controller. I’ll look into some
It actually takes 2 PWMs for the kit to work perfectly because the geometry and obviously the speed of the motors can vary. Also, this will NOT work for all motors. The motors have to have a ground separate from the motor case. A motor that is “case grounded will not work.
Since the actual motors and geometry are the influence, you can get as close with a single PWM as you would without one at all. I think that’s close enough for me. Better than the drooping single headlight door with the VACUUM system. The other potential benefit of 2 PWMS would be the ability to slow the motors down even more than with just 1. Currently, with 2 motors attached to the circuit, you can only slow down the motors so much before the power drop is too great for each motor to react. I suspect using 2 PWMS would remedy that issue slightly.
For the motors that are grounded through the case, rubber washers and bushings can be your friend. Once everything is isolated… solder your own negative wire to the case.