Datsun Roadster Forum-311s.org

Hi Guys, I have tried to fix my headlights from staying on bright and have had no luck. I have the 4 post headlight relay and single row fuse bar. Plus I was wondering if any other Datsun Headlight Relays might work in a 1600. Im sure it would have to out of a early 510, 411, or 520.
I removed the cover and the bi-metal strip will not release from the bright contact when I use the dimmer switch. I now about the grounding of the dim switch and how it works but something is not right so I want to change the relay before tearing into my wiring harness.
Lights are so bright I got to wear shades...Bill Cole

Bill,

Go open the hood.
ENGINE OFF.
Open Hood.
Turn head lights on.
Does the relay engage? (You'll hear it click).

(I assume the dimmer swith has no effect, otherwise you wouldn't have posted this question).

I suspect your wire from the relay to the turnsignal/dimmer switch
may be shorted.

RELAY COMMENT: Four Terminal relay:
ONE POWER feed (from the headlight switch)
One contact to dimmer switch (relay coil)
One to high Beam
One to low Beam

You can use a conventional relay to replace this, but even better the modern relays are SMALLER than the original. So the trick is to "gut" the original and install a smaller one inside the housing keeping everything under the hood looking stock.

Tom Walter

P.S. In 1988 while you were at a stop light, some idiot jumped out of his car and ran up and knocked on your window. Scared you half the death, sorry about that!

Hi Tom, So we have met??? I have cleaned contacts inside my dash switch and checked the dimmer with a multi volt meter and while I switch from bright to dim the is no clicking sound like there should be, like you mentioned. Indicator light stays on.
When the dimmer switch is on bright the relay coil heats up and pulls upward toward the bright contact and when the dimmer is switched back the coil releases the bimetel strip but the strip just stays upward and I can release it by hand and it looses contact but is not touching the lower dim contact. Then I put them back on bright then I hear the click and the bright are stuck on again.
Could it be a bad sealed headlight? At first I just lost my dims and drove home at night with the flashers on the once I hit the brights they have stuck on again, of course only when light switch is in secound pull position.
By now I think I have tweeked the relay contacts trying to align them for contact. So a replacement might be the best. I do have some relays from 69-70 years but the have more wires going to them. This problem has never happened before,26 years, so I am puzzled.
Thanks for you reply back and hope to get this thing fixed so I can drive the car and not worry about daylight. Bill

Bill,

Sounds like that relay is just toast.

You could wire in a common BOSCH relay. If you noticed the common replacements will have FIVE CONNECTIONS. Relay coil has two connections, and the relay contact have three (NC, NO, Common).
NC = normally closed (low beam), NO = normally open (high beam), Common being the power to the headlights.

To make a "5 terminal" relay act like the "4 terminal Datsun" Relay:
One side of the relay is connected to "common".

Tom

Your contact on the colum is not flipping on. High beams are default open circut, dim is closed. Take the switch apart and ajust accordingly. I had this problem last december. When you flip the dimmer the contact moves, if it doesn't you are stuck with one or the other.

Will

Hi guys, I finally got around to working on the lights and I fixed the Stuck on Bright problem with a relay from a 70. It has six wires going into it and the 68 had four. I split the RY wire and connected them to 2 posts and spliced into the GW wire (parklights) to have the voltage for the dimmer switch to ground out with. It works great and so far so good.
Tom thanks for the help and your time trying to figure this out. I guess the old relay decided to just go out.

Here is the 311s page for many things eleterical in nature...

http://www.311s.org/tech/electrical/elect.html