0
$\begingroup$

Good afternoon, I have recently ordered a normally closed relay to fix on my car's daylight-running lights. When the main lights come on the DLR should switch-off. Unfortunately amazon has delivered instead of a normally closed 2 normally open relays (!!?). Is there a clever way to emulate the normally closed relays functionality with two normally open relays? Thanks in advance.

regards perry

Improve this question
$\endgroup$
3
  • $\begingroup$ Wouldn't it be easier to just return the items sent in error and get Amazon to send the correct part? $\endgroup$
    – Eric S
    Commented Feb 1, 2020 at 23:42
  • $\begingroup$ @Eric: Where's the fun in that? $\endgroup$
    – Transistor
    Commented Feb 2, 2020 at 10:50
  • $\begingroup$ yes, it would be easier. unfortunately i am stuck with the parts in a remote place for now. so making the best out of it, and actually is fun to find a way to get it going still. :-) $\endgroup$
    – Perry Hall
    Commented Feb 3, 2020 at 18:24

1 Answer 1

Reset to default
1
$\begingroup$

You have a chance. This might work as a temporary solution.

enter image description here

Figure 1. Switching DLRs off with an NO when headlights are on.

How it works:

  • When the ignition is on and the headlights are off the headlamps will provide a low enough resistance to allow the RLY to pick up. The normally open (NC) contact will close and the DLRs will turn on.
  • When the headlamps are on there will be 12 V on both sides of the relay so no current will flow and the relay will drop out switching off the DLRs.

enter image description here

*Figure 2. Modification to detect both dip and high beam status.

  • The DLRs will turn on only if both DIP and HIGH are off.

Note that in both circuits I've powered the relay from a line switched by the ignition. This will avoid draining the battery when the ignition is turned off.

Improve this answer
$\endgroup$
3
  • $\begingroup$ this sounds like a good proposal. i will try to find an ignition plus in the fuse box in the engine compartment and take it from there. $\endgroup$
    – Perry Hall
    Commented Feb 3, 2020 at 18:20
  • $\begingroup$ thanks for taking the effort. i tried to upvote your post, but i have not enough reputation, as i asked what seemed like not so good questions in another threat. $\endgroup$
    – Perry Hall
    Commented Feb 3, 2020 at 18:26
  • $\begingroup$ Let us know how you get on. $\endgroup$
    – Transistor
    Commented Feb 3, 2020 at 18:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.