DIY headlight wiring harness upgrade for low $$
11-18-2010, 01:44 PM
#61
Registered User
don't worry about that diode. I didn't use it, and my highs stay on with my lows. can';t answer you about the heat though. But you might wanna use 10ga and 8 gauge wire though. and not 14g and 10 ga.
11-18-2010, 01:50 PM
#62
Registered User
edit** on my relay it says 87 and 87a.. from what ive read most people leave 87a alone? but why couldnt you run 87 to one head light then 87a to the other? Also, when i wire up my relay for my high beams(only low relay wired up) should that change anything on the oem h4 plug?
A good trick to remember- when your switch is off, 87a is always on.
11-18-2010, 01:53 PM
#63
Registered User
11-18-2010, 02:49 PM
#65
Registered User
Unless you get a five pin relay with two 87 outputs, which is what I personally prefer when wiring headlights/auxiliary lights. Two 87 outputs allows you to run one wire for each headlight instead of splicing them together. 
11-18-2010, 03:02 PM
#66
Registered User
Wired it up like yours, nothing worked saw something sparked near the fuse box checked everything now nothing works haha. Ah I even tried to run it like how it worked just on low and that doesn't even work
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
Last edited by 874runnersr5; 11-18-2010 at 03:36 PM.
11-18-2010, 08:50 PM
#67
i figured it out. it all has to do with the high-beam (h/b) indicator. when the h/b's come on, the ground is removed from the positive of the h/b indicator. this allows enough current to flow through the l/b filament and illuminate the h/b indicator, while not illuminating the l/b's themselves. however, when the l/b's are replaced with a relay, the relay is activated, causing your l/b's to come on when the h/b's are on. try adding a few high-watt resistors in parallel with the l/b relay
Last edited by irab88; 11-19-2010 at 05:07 AM.
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xxxtreme22r (11-19-2010)
11-18-2010, 08:53 PM
#68
Wired it up like yours, nothing worked saw something sparked near the fuse box checked everything now nothing works haha. Ah I even tried to run it like how it worked just on low and that doesn't even work
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
terminal 87 is normally disconnected until the relay is activated
terminal 87a is normally connected until the relay is activated
(unless you have some other, non- automotive relay)
Last edited by irab88; 11-18-2010 at 08:58 PM.
11-18-2010, 08:59 PM
#69
Registered User
you have to remember that the headlights are a common positive system. double-check that. i'm not doubting you, it's just something i would have over-looked
5 pin relays don't work like that
terminal 87 is normally disconnected until the relay is activated
terminal 87a is normally connected until the relay is activated
5 pin relays don't work like that
terminal 87 is normally disconnected until the relay is activated
terminal 87a is normally connected until the relay is activated
either way, i wired it up identical to his diagram.. and still no luck.
oh well, im more than happy with 90Watt lowbeam for now..
11-18-2010, 09:13 PM
#71
Registered User
When the relay is clicked on (providing power to the 85 and 86 terminals), THEN the 87 is powered.
Read here for a pretty good breakdown of the Bosch style relay:
http://www.classictruckshop.com/club...osch/relay.htm
Originally Posted by shaeff
When 87 is powered, 87a is not. When 87a is powered, 87 is not.
A good trick to remember- when your switch is off, 87a is always on.
A good trick to remember- when your switch is off, 87a is always on.
Check out http://danielsternlighting.com/ I've been using dual 87 output relays for wiring stuff like this for years. (when I say dual 87 output, I mean straight 87, not an 87 and 87a.
) They're the best for doing jobs like this.
11-19-2010, 03:43 AM
#72
Registered User
i figured it out. it all has to do with the high-beam (h/b) indicator. when the h/b's come on, the ground is removed from the positive of the h/b. this allows enough current to flow through the l/b filament and illuminate the h/b indicator, while not illuminating the l/b's themselves. however, when the l/b's are replaced with a relay, the relay is activated, causing your l/b's to come on when the h/b's are on. try adding a few high-watt resistors in parallel with the l/b relay
your a genius, well I guess I could figured it out by looking that the factory wiring diagram as well. But was not worried about it, I like the L/B on with the H/B.
But it does explain why my H/B indicator is now dimmer since doing this mod.Wired it up like yours, nothing worked saw something sparked near the fuse box checked everything now nothing works haha. Ah I even tried to run it like how it worked just on low and that doesn't even work
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
edit* wired it back up to when just low works for the time being.. blah.. i don't get this i wired it exactly like yours and nothing worked..
Did you check your fuses after you lost power? What size fuses did you use for low and high beams? You will need a minimum of a 20 amp fuse for your lows since your low beams will draw about 15 amp, and you high beams are gonna require nothing less than a 30 amp fuse since they are going to draw roughly 22 amp.
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irab88 (11-19-2010)
11-19-2010, 04:54 AM
#73
Another note- you've got that backwards. When the relay is NOT powered, 87a IS powered as shown here in an illustration of a relay- you can see that the 30 terminal is connected directly to the battery and has a braided wire going directly to the steel plate, which, when the relay is not energized is in the open position, thus making contact with the 87a terminal.
...
...
terminal 87 is normally disconnected until the relay is activated
terminal 87a is normally connected until the relay is activated
terminal 87a is normally connected until the relay is activated
as for the dual 87 relays, awesome! i didn't know they made those. now i've got a new component to try out
11-19-2010, 07:19 AM
#74
Registered User
your a genius, well I guess I could figured it out by looking that the factory wiring diagram as well. But was not worried about it, I like the L/B on with the H/B. But it does explain why my H/B indicator is now dimmer since doing this mod.
You are only using 1 of the original headlight sockets right?
Did you check your fuses after you lost power? What size fuses did you use for low and high beams? You will need a minimum of a 20 amp fuse for your lows since your low beams will draw about 15 amp, and you high beams are gonna require nothing less than a 30 amp fuse since they are going to draw roughly 22 amp.
But it does explain why my H/B indicator is now dimmer since doing this mod.You are only using 1 of the original headlight sockets right?
Did you check your fuses after you lost power? What size fuses did you use for low and high beams? You will need a minimum of a 20 amp fuse for your lows since your low beams will draw about 15 amp, and you high beams are gonna require nothing less than a 30 amp fuse since they are going to draw roughly 22 amp.
11-19-2010, 07:45 AM
#75
Registered User
Yeah I caught that now. I was wicked tired last night when I posted that. LOL. We absolutely said the same thing in different ways. I gotta stop tired-posting! Yeah man, they're fantastic. So much better than cramming two thick wires into a single crimp connector or splicing two wires onto a single output wire when using a relay harness (which I highly suggest doing!)
Use some RTV to seal the back where the wires come out, and dielectric grease in the terminals- it'll never fail on you from corrosion. Using that method I've had relays mounted under the truck before going through many NE winters and never had an issue with a failed relay or corrosion on the wiring/terminals.
Last edited by shaeff; 11-19-2010 at 07:48 AM.
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irab88 (11-19-2010)
11-19-2010, 08:30 AM
#76
Yeah I caught that now. I was wicked tired last night when I posted that. LOL. We absolutely said the same thing in different ways. I gotta stop tired-posting! Yeah man, they're fantastic. So much better than cramming two thick wires into a single crimp connector or splicing two wires onto a single output wire when using a relay harness (which I highly suggest doing!)
Use some RTV to seal the back where the wires come out, and dielectric grease in the terminals- it'll never fail on you from corrosion. Using that method I've had relays mounted under the truck before going through many NE winters and never had an issue with a failed relay or corrosion on the wiring/terminals.
11-19-2010, 10:27 AM
#77
Registered User
Hella makes some, and Daniel Stern (I linked to his site earlier) sells them too. There are a few different manufacturers. My local AutoZone has them sometimes under "Baja Relay"- the package has a picture of a Baja truck with lights all over it. They are reasonably durable- I've yet to have one fail on me.
I try to go through Daniel Stern whenever I can, though, as he will NOT sell you a product that is of poor quality. That guy really knows his stuff.
I try to go through Daniel Stern whenever I can, though, as he will NOT sell you a product that is of poor quality. That guy really knows his stuff.
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irab88 (11-19-2010)
11-20-2010, 05:23 AM
#79
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So I'm working on my harness today (timely thread btw as I had ordered my housings and bulbs a couple of weeks ago) and I havea question. One of you said that your HB are coming on with your LB even without a diode. Now I do not want my LB on with my HB so who's diagram should I follow?
