Monday, January 21, 2013

More Electrical work - Auto Headlights

Dateline - January 19, 2013 - Worked on more electrical wiring this weekend.  The goal, install the automatic headlight system.  I purchased an aftermarket Automatic Headlight with daytime running light system last year.  The kit includes a main CPU, a photosensitive diode, an override switch, a set of relays for Headlights and Sidemarkers, and wiring to connect it all together.  The Unit has a lot of features including:

- Automatic headlight/sidemarker

- Daytime running lights (headlights only during the day)

- Automatic lights on with windshild wiper turn on (required in some states)

- Interconnection with security system

Since I'm not installing a security system, and didn't want the headlights to come on with the wipers, I removed those wires from the wiring harness.

Next, I determined where I wanted to mount the unit.  I'm trying to put all my electrical items in the cavity in the center console, so I found a good place to mount the unit, on the bracket used originally for the Air Flow control levers (left and right).

My next decision was were to put the relays.  Well, this car is going to have a lot of relays!  I already have a relays for the ignition cutoff switch, and one for the transmission torque lock, and now I have two more for the automatic headlights.  As I thought about the new wiring, looked at schematic, and the original wiring, I realized that the original had all the headlight power coming from the battery, into the headlight/sidemarker switches then to the fuse box and to the lights.  This means that the two switches have to carry all the current used by the headlights and sidemakers!  That's a lot of amps!  Even thought the new Aircraft switches could probably take this sort of power, I didn't want to push that kind of current through the switch.  This means two more relays.  I will also want some relays for interior lights and auxillary power.  That makes a total of eight relays.

So, I decided to create a relay frame that I could mount on the transmission tunnel access panel.  This required some more sheet metal fabrication including cutting, bending, filing, welding captive bolts onto the frame and the access panel, and painting.  But now I have a great place to put all eight relays, and can even put two to four more there if I want.





The last trick of the day was doing the wiring, which required some spelunking around the old wiring harness.  I had to find where the hot came into the light switches and then were the headlights and sidemarkers came out.  Turns out the Hot and Headlights are in one plug, while the sidemarkers are in another, both on the left hand side of the car.  Since I don't want to cut the plugs from the original center instrument cluster (would really impact resale value), I'm creating my own wrirng by building pins that will plug into the existing harness plugs.  Once I have all the wires set, then I will build a plug around them using Silicon or RTV.

I still have a little wiring to do.  I have to wire the automatic headlight cutoff switch and the actual headlight and sidemarker switches.

I'm pretty happy with how this worked out.  Next I'm either going to tackle the heater fan wiring or the cruse control system.