headlight ? mix h4/9004 & sealed beam high???

[robertglines1]

When I installed the pilot conversion shell and h4/9004 bulb my high beam (sealed beam) came on very dim when it should not have been on at all..Removed h4 & reinstalled sealed beam and all worked as should.Called pilot customer service they acted as though they had not had problem in 3 years guessed at all bulbs should be h4 style...help I can't see what difference it would make until I turned on the high beams....

[PCC]

Usually, when a bulb that should not be lit, is lit dimly, then the grounding for the light that SHOULD be lit is faulty. It is the current from the 'should be lit' bulb that is looking for ground that finds it through the other, non-lit, bulb, causing some current to flow through the non-lit bulb causing that bulb to light, only dimly because not all the current is using that (un-lit) bulb as its ground, but enough is to light it with some of the voltage/current.

As long as the bulbs are the correct voltage, and are wired correctly to operate as low or high beams, the type of bulb should make no difference.

I  hope that all makes sense.

The bottom line - check your grounds to each lamp. Check for corrosion, and solid connections, at each end of the wire.

[robertglines1]

Thanks for the info sort of what I was thinking but not sure..Will run new grounds to chassi and re test will report results ...could be a couple of days weather turning cold here and fire sure feels good..

[robertglines1]

Can a new ground be run to the frame or does it have to run to the 12 headlight converter.I have a ground wire that looks suspect.?I'm working on a 89 prevost 24volt system with 12 volt headlights.

[PCC]

All the vehicles I have seen with 12 volt lights, still use the same chassis ground and take the positive (+)12 volts from either a converter or from a tap between the batteries at the 12 volt point.

Use a meter to test lights. Set for OHMS, and test from the ground connection (-) of the lights to the chassis. If the meter reads 0 (zero) OHMS, then the lights are using the chassis ground.

Also check for 12 volts from the positive (power) side (+) of the wiring (to the lights), to the same chassis ground. If that works (reads 12 +/- volts), then you can be fairly certain that a chassis ground is correct.

Keith

[robertglines1]

Established good grounds :still does it. put sealed beam back in and everything is back to normal...h4 are 60 watt.wonder if converter is not big enough to handle??put in new sockets also...soldered all wires...which of the three prongs on back is the ground(maybe ground in different location on h4)

[robertglines1]

feel like I'M dumb.. the ground on the h4 is in a different location..changed to a h4 plug and all is good...hope this helps someone else out..Don't know how bus was wired but the sealed beam worked like it was but the h4 50w would do strange things..buses are good!a little challenging at times.

[PCC]

I am confused. All sockets' wirings should be the same, and if both lamp systems are 12 volt, and if the grounds are good, there should not be an electric bleed over to the other lamps.

Sorry my advice has been fruitless in this case, but you have me really thinking about how this would work to do what you describe.

The hign beam lamp sockets should have only two wires, one ground and one power.

The low/high beam lamp sockets should have three wires, one power for low beam, one power for high beam and one for ground.

If all the grounds (four of them, one for each lamp socket) are connected to the chassis and the socket well at both ends, and the low beams are connected to the low beam power source well at both low/high bulbs, and the high beam is wired to the high beam power source at all four bulbs, the only possibility I know is that the high beam lamp is getting power from somewhere else, because I only know that if the power for the low beam goes through the filaments of the low beam, and finds no ground at the low/high bulb socket, the power goes through the high beam filaments of the low/high bulbs, then through the high beam filaments of the high only bulbs to the high beam bulb ground.

That is the only dim your headlights circuit I can imagine, because you said they work right when the original sealed beams are returned into the circuit, and that usually eliminates any other power source.

Guess I would have to be there, huh?

Sorry.

[PCC]

See that you got it - well done !!

Have a great day.

[robertglines1]

If I had not got new sockets I would not have figured it out(for h4) all works as should..thanks for helping me reason thru it...

[FloridaCliff]

Robert,

I would recommend running grounds back to the distribution panel.  On my conversion I have separate grounds for each circuit.

The OEM installation is to usually use the chassis for ground.  This works but is by no means "best practice".

Make yourself up a long jumper with alligator clips on each end, attach one end to the ground distribution panel and the other to the items ground you are working on.  This will quickly let you know if one of the many chassis ground connections have failed.  Its also good to temp a wire until you get home where you can make a repair under more relaxed conditions.

I would guess that 90% of the DC problems I have fixed for myself or others have been ground issues.

Cliff