Dome Light and Door Switches

Contributed By: William Marotta

ABOUT This Article:
This article is about the process of removing, restoring and reinstalling the Dome Light, as well as the door switches that control it, in the Datsun 240Z.

(Written 15 Oct.99)
(1st up-date 23 Oct.99)

The dome light housing is not screwed in place. The dome light housing is pressed into position and is held in place by four "tabs" that are part of the dome light housing.

To remove the housing use a flat blade object, like a screwdriver, insert between housing and roof vinyl. Lever the housing part way out. Move flat bladed object to oposite side of housing and repeat. After I had the housing part way dislodged I grasped with fingers in gently pulled from the roof. There are three wires attached to the housing. Carfefully remove the three wires.

At this point I wanted to remove the plastic lens from the housing. The only way I saw to do this was to remove the metal trim ring from the housing. There may be another way to remove the housing lens. To remove the metal ring from the housing you have to un bend two of the locking tabs. I used a pick and ended up with a couple of new holes in the palm of my hand. After I had removed the chrome trim ring I was then able to separate the lens. I wash and clean plastic parts in water with no other chemicals. You may wish to use other cleaning methods.

The switch is working well in my car and I could not see a non destructive way of taking apart the switch, so i left that alone. The other parts of the housing were in good condition and I did nothing more to the housing.

When you check your housing see that the rivets that hold the electrical contacts/wires are tight. To correct loose rivets you will need a small punch about 3mm in diameter at most and not less than 1mm. A small hammer, if you "stake" the rivets with too much force you will probably shatter the plastic housing. Be careful and be inventive.

After cleaning the lens, place the lens into position and depress once to make shure it is able to activate the switch. This will confirm you have the lens in proper position. replace the metal trim ring. Bend the two tabs back down. Reattach wires, and press the housing back in to place in the roof panel.

To prevent damage to paint, vinyl and plastic parts I often put tape, cloth or leather around my tools. I spent 40 minutes just on the courtesy light.

Courtesy Light Switches:
The passenger door courtesy switch is the simpler of the two so I will start there. The wire for the switch is black in color and can be found above the right side knob for the fresh air vent. The wire comes out of the right side kick panel, there are many wiring connectors in this area, look for a single black wire by it's lonesome. Unplug this wire. Open the passenger door if you have not already.

You can see the switch in the front of the door opening about two thirds of the way up, it is chrome with a white plastic plunger. I used a very sharp knife with the blade covered by a layer of masking tape so as not to mar the paint. Use the sharp edge of the knife to pry up just a little on the edge of the switch, between the paint and the chrome, then go to the opposite side and do the same. Use a rocking like motion to work the switch out of its hole.

Time for a short side bar here. The switches are the ground connection to the courtesy light. The light has power all the time. The hole that the switch plugs in to is the ground. If there is rust or a poor connection of the outside of the switch body to the metal that is the hole the switch plugs into the switch may not work. The wire you unplugged is the gound connection. When I get to painting this car i will probably use a light grease around this opening to seal out water in help in rust prevention. You might want to consider some sort of body caulking or sealant instead of grease. I assume that if a sealed switch is ever needed to come out it will be that much more difficult to get it unsealed and off the body, that is why I used the grease and not a sealant. Consider also the effects of sealant and the electrical connection of the body of the switch and body of the car.

The wire is attached with a singe phillips head screw. Remove the screw. Under the screw is the wire end/contact. What is left is a cylinder and the plunger and what I will call the end cap. The end cap is the chrome part that you see when you open the door. My door switches no longer moved and this is why I disassembled them. If your switch still has springyness to them you may want to avoid this... Bend each tab, there are about 8 or 9 of them, so that when you are finished the tabs look like the petals on a daisy opened up and the cylinder in the middle of it all.

At this point I was able to separate the end cap from the body of the switch. The plunger has a steped portion, two washers, and a spring. All fo this should now come apart. Did you see where that spring whent? I hope so. The spring and washers on my door switches were rusted in the closed position and had to be replaced. I wanted to use brass washers instead of the steel ones that were original. I could not find proper sized brass washers at the local hardware store here. I did find stainless steel and that is what I used, sized in metric. The english dimensioned washers did not fit well. The metric sized ones were correct for inside and out side diameters.

A note on springs. The wire diameter has the largest effect on spring pressure or tightness if you will. If you need to get the closest one, keep in mind, try to get the wire diameter and the outside diamter of the spring the same. If you get a spring of too large outside diameter it will not fit the switch body. If you have gotten this far you should be able to use your intution of what to do if faced with a NOT EXACT replacement.

I could only find a spring with the outside diameter the same as needed, the wire diameter of the spring was like a thousandanth of an inch larger. Put that into perspective note book paper is about three to three and half thousands of an inch thick. I had to buy a spring much longer than needed and then cut to length. The first one was too short, I felt the spring did not privde enough force to ground the contact, so the next one was a smidge longer. I am sorry I cannot give dimensions of this stuff but if you buy a different spring than I did you will not be able to use the same dimensions. First place one washer on the plunger, then the spring, then the second washer. Put plunger and spring assembly into the body of the switch and for now just put the end cap over it all.

Test the plunger. Is there enough force to the plunger? Do you need to cut a longer or shorter spring? At this time I put a thin layer of grease in side the body of the switch, my switch had some rust in it and I wanted to prevent as much of that as I could. Nissan did not have grease in there so this might be a bad idea. I wonder how much road dust will stick to that grease and ball up the works in the future? If every things seems good to go put the end cap back on and bend all those petals back to original position.

Take the wire you removed and use a scotch brite pad to remove corrosion where the contact touches the switch body when the door is open. Reattach wire. Insert switch body into hole. Yea right! easier said than done. Remember the petals that you bent outward? Well this is what I did. Use a small zip tie, you know those plastic wire tie thingys that make a "zip" sound when you pull them tight. I used the zip tie to hold the petals closed untill I could get all the petals started in the hole and then cut the zip tie with an exacto knife with the pointy blade in it. Remember to always cut away from you.

So i did all this and the damn light still did not always work.... I grabbed the plastic plunger and rotated clockwise about 20 degrees and anticlockwise about 20 degrees, now the light is doing it's thing. Just this might work if the springs in your door switches are not working...

The drivers door switch has a couple of other parts to it and I will turn that in later. thank you william