LED 9004 bulbs

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LED 9004 bulbs

March 22, 2022, 09:27:56 AM

Anyone had any success with LED bulbs in the 9004 style? There is so much junk out there.

I currently have good clear lens with Silverstars and a relay harness for full battery voltage.

Re: LED 9004 bulbs

Reply #1 – May 19, 2022, 05:56:27 PM

Can you elaborate on the full voltage part?
I bought an h4/9004 halogen coversion kit for my tbird that im putting in with the intention of going with leds down the road if im not satisfied with the 55w halogens.
The led lights i had originally are the whole housing kind and not the most aesthetically pleasing thing to look at so i went with a conversion with the potential to upgrade to leds and still look like halogen housings when not on..

Re: LED 9004 bulbs

Reply #2 – May 23, 2022, 11:55:15 AM

The way the cars are built, the voltage to the headlights pass thru the headlight switch and aged old wiring. People run new wiring with relays. This allows full battery voltage to headlights vs. the voltage drop with the stock setup.

Re: LED 9004 bulbs

Reply #3 – May 23, 2022, 08:17:44 PM

Interesting.
I tried to put in my h4 conversion this weekend and the low beams dimmed significantly when the high beams were used, which also set off the "low beam out" warning light on the dash.
I think i have other issues impeding this on my end.
I took it all back out and put the halogens back in, ill figure that stuff out in the diagrams later when i have time.

Re: LED 9004 bulbs

Reply #4 – May 23, 2022, 08:56:54 PM

Back when I did the H4 conversion in my car, I also installed a relay/fuse panel at the time. In it was a separate relay for LO and HI beams, as well as for the fogs.

Re: LED 9004 bulbs

Reply #5 – May 24, 2022, 04:19:19 AM

Quote from: Chuck W on May 23, 2022, 08:56:54 PM

Back when I did the H4 conversion in my car, I also installed a relay/fuse panel at the time. In it was a separate relay for LO and HI beams, as well as for the fogs.

I have the lights out warning system so i would probably have to bypass all that to do it right.
According to the 83 evtm there are resistance wires between the multi function switch and the warning module that the module uses to sense specific voltage to turn on the warning lights.

Re: LED 9004 bulbs

Reply #6 – May 24, 2022, 07:23:01 AM

I think I'd rather have good lighting than to mess with the bulb outage stuff.

On mine, the switch was old and the lights would cut out whenever I had the HI beams on too long.

You may be able to fool it, but I'm not sure it's worth the hassle.

Re: LED 9004 bulbs

Reply #7 – May 24, 2022, 09:17:56 AM

When you have the optional System Sentry, the resistor wire for the "lights out" warning is calibrated for halogen bulbs. Using any other non-halogen bulb in one of those circuits (including an LED bulb) will automatically kick the warning light on. So...to get it to work correctly with an LED bulb is going to take some engineering for sure, if it's even possible. I am not sure if the resistor wire can be used with an LED bulb...somehow that seems counterintuitive. Running a separate non-resistor wire might help but again, that kinda complicates things with the harnesses and terminals.

Hopefully one of our electrical gurus here can give us some better insight.

Re: LED 9004 bulbs

Reply #8 – May 24, 2022, 10:10:42 AM

Quote from: Ductape91 on May 23, 2022, 08:17:44 PM

Interesting.
I tried to put in my h4 conversion this weekend and the low beams dimmed significantly when the high beams were used, which also set off the "low beam out" warning light on the dash.
I think i have other issues impeding this on my end.
I took it all back out and put the halogens back in, ill figure that stuff out in the diagrams later when i have time.

My sons 87 Crown Vic. Put in H1 and H4 glass housings with higher wattage bulbs and a ebay H4 wiring harness. Works amazing. Had to move a couple wires in the wiring plug, but no big deal.