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Discussion Starter #1
Swapped my Delta bulbs to Hella 55/100s today and I was concerned about the 100w and the canbus getting into an argument so I got off my butt and finally built a wiring harness for the headlights.
Now they pulsate like a car with too much stereo for the electrical system.
But it does it with the jeep running and nothing else on.
Doesn't seem to be any rhyme nor reason, they just fluctuate occasionally.
They do it at idle or while driving, hi or low beam.
Also they seem to dim a little as soon as I come off idle (backwards of what I would expect if it were a power problem)

Harness is simple - 10G from battery to pax headlight area split to 2 40 amp relays (one hi beam, the other low) driven off of the stock headlight plug on that side, then the relay outputs split to the headlights.
All 10G wires and the headlights themselves are grounded to the body within 12" of the bulb.

Maybe need to I run a ground back to the battery?

The light output is FREAKIN ASTOUNDING!
Hi beams look like I have my off road lights on!
Just need to stabilize it somehow.

I just don't know why they would be fluctuating with a 10G run essentially straight to the battery.

Any ideas?
 

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I would have to say you most likely have a ground issue. When you ran the ground wires to the body did you clean the paint away first?
 

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Discussion Starter #3
yeah a ground issue is about all I could think of
the ground on the passenger side is actually a factory ground point, I took the nut off and slipped the ring terminal over top of the factory braided ground/ring terminal.
Drivers side was a body bolt, they baint the body after its assembled so there's no paint under the bolt.

I'll try cleaning the ground points.
I'll also try running a temporary ground wire from there to the battery

I need to look closer and see if it's both lights or just one
 

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Are they flickering like the relay is kicking in and out? If so, I would try putting a diode in series with the relay coil, and a capacitor across it(the relay coil). If this is unclear let me know and I can explain better.
 

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Discussion Starter #6
Are they flickering like the relay is kicking in and out? If so, I would try putting a diode in series with the relay coil, and a capacitor across it(the relay coil). If this is unclear let me know and I can explain better.
nope, not like the relay is dropping
just like I said, they are dimming a little like when you have too much amp and not enough alternator/stiffening cap
weird part is that they dim when you bring the rpms up off of idle instead of getting brighter like you would expect with a lack of power problem

They don't seem to be doing it when the engine is off, I need to do more testing and find out for sure
I just did the harnesses and took it for one test drive
 

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Are they flickering like the relay is kicking in and out? If so, I would try putting a diode in series with the relay coil, and a capacitor across it(the relay coil). If this is unclear let me know and I can explain better.
My pre-made Susquehanna wiring harness came with the diode/capacitor installed to the relays. It's 12 gauge and I have zero problems with the 130/100 Hella Yellow Star H4 bulbs. They are bright as heck, and I have never noticed them flicker a single time.
I was running the Osram 85/80 bulbs which I was very happy with. Changing to the Yellow Star bulbs gives the light a warmer output, and with the increase in wattage I haven't lost any range on low or high beam.
I also added Osram 55w all weather bulbs to the FabFour bumper mounted 90mm Hella fog lights. They are a good match to the Yellow Star Hella bulbs, but I'm planning on some yellow tint film on them as well.
 

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irate4x4 dot com
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put a cap across the trigger wire for the relays.

you are not getting flicker because it's filament bulbs

it's the same issue though
 

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Basically what everyone else has said....

Use an elecrolytic cap, 100uf 35v or higher across the relay coil, observe polarity, plus to plus, ground to ground. Then put a 1N4001 or higher diode in series with the positive lead to the relays. This keeps the computer happy. The signal to the lamps is PWM (pulse width modulated), you can check the frequency if you have a counter. This should solve the problem.
 

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Discussion Starter #11
Thanks for the replies guys, I'll try this tonight assuming radio shack has what I need.
Kinda explains why I was seeing 9-10V on the low side and 12.x on the hi side while on hi-beam and vice versa at the factory plug
 

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if I remember correctly from jk-little pecker, you had to put a resistor on your trigger wire (from the headlight plug because the can bus is searching for the correct voltage. can't remember what size cap to use but im pretty sure that is you problem
 

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I have a relay on both high and low beams triggered by the stock wiring.

I only added a capacitor... no diode and no resistors. Been this way for about a year with no issues, no codes, nothing.
 

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yeah when I swapped to HID set up the high beams would flicker like crazy, added the cap and has been perfect since. if you can't find the correct cap to use pm me and ill go through all my cibie stuff that I haven't installed there are two or three in the bottom of that tangled mess of wires.
 

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I have a relay on both high and low beams triggered by the stock wiring.

I only added a capacitor... no diode and no resistors. Been this way for about a year with no issues, no codes, nothing.
The diode is a gate for the canbus system. Relay coils produce brief high voltage spikes when switched off. The diode keeps the spike from running backwards through the system.

Normally the diode is connected "backwards" across the relay coil to provide protection. Current flowing through a relay coil creates a magnetic field which collapses suddenly when the current is switched off. The sudden collapse of the magnetic field induces a brief high voltage across the relay coil which is very likely to damage transistors and ICs. The protection diode allows the induced voltage to drive a brief current through the coil (and diode) so the magnetic field dies away quickly rather than instantly. This prevents the induced voltage becoming high enough to cause damage to transistors and ICs.

50 cents is cheap insurance.
 

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daniel sterns website has diagrams and all kinds of info also.
 

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Discussion Starter #17
went to crackshack and bought caps and diodes - whopping $4.06!
I'll install them and try it tonight
thanks for the info guys!
 

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Watch the polarity of the diodes also, the band goes to the relay side.
 

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the pigtail connectors that came with the relays I bought (in bulk pack of 10 or 20 a few years ago) have the diodes across the coil already. I think they were Hellas also.

But I was under the assumption that someone was referring to inlining a diode on the trigger wire
 
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