what am i doing wrong?
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=115880
Printed Date: May 20, 2025 at 12:40 AM
Topic: what am i doing wrong?
Posted By: hondabeat
Subject: what am i doing wrong?
Date Posted: August 24, 2009 at 5:40 PM
I'm in the middle of completely rewiring my headlamp circuit with new H9 lights and DRL's combined with the turn signal bulb. So far, the DRL and turn signals work perfect with my ig1 relay. I have another SPDT relay hooked up to the ground wire (through 86 to 85) coming from my lo and hi beams which when activated kills the DRL power (connected on 87a) so they do not stay on with the normal headlamps. This is where the problem is, when I switch on the lo or hi beams, the relay activates and switches the DRLs off, but the headlamps do not come on! If I disconnect the ground wire from the relay and just bypass the relay the headlamps work fine.. Why can't the lights work while also powering the relay coil on the ground? Here is a diagram I made of the portion of the circuit I am talking about:

Replies:
Posted By: howie ll
Date Posted: August 24, 2009 at 5:57 PM
Try this headlight 12v.+ power high and low join via 2N5405 diodes, bars towards relay, term 86, ground 85,12v+ power to DLR to 30, out to DLR from 87a.
Posted By: hondabeat
Date Posted: August 25, 2009 at 7:36 PM
howie ll wrote:
Try this headlight 12v.+ power high and low join via 2N5405 diodes, bars towards relay, term 86, ground 85,12v+ power to DLR to 30, out to DLR from 87a.
hmm.. are you sure that is the correct part #? I searched a half dozen electronics stores and nobody has even heard of it.. At the largest electronic part store I went to, after a lot of searching one of the guys there came up with this part: NTE159 and said that it might be the same thing. They still have to order it in, is this the same thing??
Thanks.
Posted By: howie ll
Date Posted: August 26, 2009 at 3:40 AM
Er no, they are simple 3 amp didoes, 2N54xx series. It's to stop the feeds from lo and hi interfering with each other.
Posted By: dualsport
Date Posted: August 26, 2009 at 9:07 PM
Probably meant 1N5405, instead of 2N5405, which is a transistor.
Posted By: dualsport
Date Posted: August 26, 2009 at 9:16 PM
For the suggested modification, pretty much any diode should work. The only current they need to pass is the relay coil current, which is relatively low.
A 1N4001 is a cheap standard 1A diode that should be easily available just about everywhere.
Posted By: howie ll
Date Posted: August 27, 2009 at 3:32 AM
You're right dualsport, I thought the coils might draw more.
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