Full info on my headlight level manual override control:
01-22-2007, 06:34 PM
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Full info on my headlight level manual override control:
Background:
All US spec cars with HID headlights are required by law to have an automatic vertical aim control to avoid dazzling oncoming drivers when the trunk is loaded for instance.
This is accomplished in the S4 using a Phillips TDA3629 servomotor controller. Each headlight contains a motor which moves its inner housing according to a supplied common control signal. Here are the operational details:
<img src="http://toyguy.o-f.com/images/operation.jpg">
By intercepting this signal before it reaches the headlights the aim can be manually controlled. Below is the circuit diagram:
<img src="http://toyguy.o-f.com/images/manual_adjust.jpg">
The main control pot(R3) is a Radio Shack item and is an audio control pot with SPST switch built-in. This switch acts to set the aim in the auto mode when turned to the "off" position. In any other position, the aim is in manual mode. Turning the pot clockwise from "off" raises the headlights. Below is a shot of the wiring harness. You can see the trim pots for level and range. They are adjusted so that the main control functions over its full range and raises the headlight aim to the max when the main control is fully clockwise.
<img src="http://toyguy.o-f.com/images/harness.jpg">
Here's where I located the control **** so as not to destroy anything expensive in the interior. It's shown in the "off" (auto) position and with the ridge on the **** it's easy to set without looking. It's adapted from a discarded toaster oven :-)
<img src="http://toyguy.o-f.com/images/control_knob.jpg">
Looking at the harness, the bundled wire is connected to a local ground near the fuse box. The other 3 are routed across under the dash, over the glove box, and down to the right kick panel connector area. This is very easy to do with a fish wire. The connection area is shown below.
<img src="http://toyguy.o-f.com/images/wiring_area.jpg">
The kick panel is attached by 2 Phillips-head screws, one up near the top, and the other behind the little cover near the bottom. Remove the screws and pull rearward on the lower portion of the panel cover about 1/4". Then it will lift up and out.
Coming out of the blue connector, located at pin position 5, is a brown wire with white stripe. This is the control signal voltage which leads to both headlight servomotors.
This wire is cut, and the new control is spliced in. The input signal will come "out" of the connector, will go through the new control, and back to the cut wire, which leads eventually to the headlights. The wires are soldered and taped of course.
I'm also using the black with green stripe wire located in the same blue connector at position 1. This is the V+ wire. This way there will never be any power going through the control **** with the headlights off.
--------------------------------
It has been working great for 3+ years and I've never had to make any adjustment after the initial calibration. It's not difficult to do with a little motivation and the rewards make it well worth it IMHO! Have fun.
All US spec cars with HID headlights are required by law to have an automatic vertical aim control to avoid dazzling oncoming drivers when the trunk is loaded for instance.
This is accomplished in the S4 using a Phillips TDA3629 servomotor controller. Each headlight contains a motor which moves its inner housing according to a supplied common control signal. Here are the operational details:
<img src="http://toyguy.o-f.com/images/operation.jpg">
By intercepting this signal before it reaches the headlights the aim can be manually controlled. Below is the circuit diagram:
<img src="http://toyguy.o-f.com/images/manual_adjust.jpg">
The main control pot(R3) is a Radio Shack item and is an audio control pot with SPST switch built-in. This switch acts to set the aim in the auto mode when turned to the "off" position. In any other position, the aim is in manual mode. Turning the pot clockwise from "off" raises the headlights. Below is a shot of the wiring harness. You can see the trim pots for level and range. They are adjusted so that the main control functions over its full range and raises the headlight aim to the max when the main control is fully clockwise.
<img src="http://toyguy.o-f.com/images/harness.jpg">
Here's where I located the control **** so as not to destroy anything expensive in the interior. It's shown in the "off" (auto) position and with the ridge on the **** it's easy to set without looking. It's adapted from a discarded toaster oven :-)
<img src="http://toyguy.o-f.com/images/control_knob.jpg">
Looking at the harness, the bundled wire is connected to a local ground near the fuse box. The other 3 are routed across under the dash, over the glove box, and down to the right kick panel connector area. This is very easy to do with a fish wire. The connection area is shown below.
<img src="http://toyguy.o-f.com/images/wiring_area.jpg">
The kick panel is attached by 2 Phillips-head screws, one up near the top, and the other behind the little cover near the bottom. Remove the screws and pull rearward on the lower portion of the panel cover about 1/4". Then it will lift up and out.
Coming out of the blue connector, located at pin position 5, is a brown wire with white stripe. This is the control signal voltage which leads to both headlight servomotors.
This wire is cut, and the new control is spliced in. The input signal will come "out" of the connector, will go through the new control, and back to the cut wire, which leads eventually to the headlights. The wires are soldered and taped of course.
I'm also using the black with green stripe wire located in the same blue connector at position 1. This is the V+ wire. This way there will never be any power going through the control **** with the headlights off.
--------------------------------
It has been working great for 3+ years and I've never had to make any adjustment after the initial calibration. It's not difficult to do with a little motivation and the rewards make it well worth it IMHO! Have fun.
01-22-2007, 06:46 PM
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Why not ??
1) I frequently drive on rural unlit roads at night with little traffic. Tweaked upwards, the increased visibility is fantastic even with high beams on, but I don't even need them. It's easy to flip them down for traffic.
2) I have ability to hassle cars in front of me by beaming the HID's in their mirror.
3) In daylight, during marginal conditions, it makes the car mega-visible to other traffic when adjusted high.
4) Why not? It's just something else to play with, and I'm Toy Guy.
2) I have ability to hassle cars in front of me by beaming the HID's in their mirror.
3) In daylight, during marginal conditions, it makes the car mega-visible to other traffic when adjusted high.
4) Why not? It's just something else to play with, and I'm Toy Guy.
