Headlight Bulbs Not Getting Enough Power

[Donnie Lerch]

Hi everyone! I recently bought some high power headlight bulbs for my 1991 Ford Ranger XLT. They are the 9004 bulb type. Since I installed them, I noticed that the truck is thinking I have my high beams on even when I only have the lights on low beam, also I have no high beams, when I switch to high beams the bulbs actually get slightly dimmer. Anyone have any ideas on how to fix those problems? Is there a way to give the headlights more power or something? Thank you for any help you can give! 🙂

Topic

[college man]

When you put on the high beams does the blue indicator light come on?

[Donnie Lerch]

The high beam indicator is already on when I have my low beams on, it doesn’t brighten when I switch to high beams.

[college man]

first check your fuses. sounds like a ground issue.
see if this helps.

http://www.justanswer.com/ford/28men-1991-ford-ranger-headlights-won-t-work-pull-high.html

[Donnie Lerch]

Okay, I’ll check that. The fuses should be alright though and I haven’t changed any grounds, just a simple bulb swap. I think the headlight just aren’t getting enough power.

[college man]

If you have a meter check to see what power you are getting.
you may need to clean power and grounds.

[Donnie Lerch]

I already tested it and I believe I was getting around 9.6 on low beam, then I would switch on my high beams, it would jump up to around 10.5 and then go back down.

[Donnie Lerch]

I guess my real question is how can I give the lights more power?

[george gonzalez]

The bulbs have a different pinout than your original bulbs, so the bulbs are cross-feeding from the low to the highbeam wires.

Go back to your original bulbs. Don’t try putting in larger ones, your wires, connectors, fusebox, switches, reflectors, lamp sockets, lenses, and relays are not designed for the higher current. Higher power bulbs may work for a while, but after an hour you might have melted wires or blown fuses.

You CAN put in more efficient bulbs that have the same pinout. Look for bulbs with more lumens but the same or lower current or wattage.

[Donnie Lerch]

What do you mean by “pinout”?

[college man]

[quote=”DonnieLerch” post=117598]I guess my real question is how can I give the lights more power?[/quote]

You should have what the alternator is putting out. You have a voltage drop
somewhere. Time clean everything up.

[george gonzalez]

Well I rushed my answer a little bit. It could be one of two things–

It could be a different pinout, meaning that the lamp pins are not arranged as lo gnd hi, but instead gnd lo hi as an example. If the pins are swapped this way then when you plug in the lamp one of the filaments is bridging from lo to hi beam and you get exactly the symptoms you mention.

There is another possibility– if the gnd connection isn’t making contact, then you get the same effect– the current flows from the low beam filament through and back up the high beam filament to the other bulb. And you get the blue high-beam indicator partially glowing.

[Donnie Lerch]

Okay that makes sense. The high beam indicator is fully glowing constantly, so I guess that means that the pinouts are different? Is there a way to check and see if a certain bulb has the same pinout? The old bulbs were 45/65w bulbs and the new ones are 80/100w. Is the high beam indicator coming on since the new bulb’s low beams are higher powered than the old ones?

[college man]

If the beam indicator is always on. Your combo switch is
stuck in high beam or you have it on. Try to turn it off.

[Donnie Lerch]

Combo switch? I know the high beams switch isn’t on, I’ve toggled the switch in the cab several times and it doesn’t do anything except dim the lights slightly when they should get brighter for the high beams.

[Lorrin Barth]

If it was fine before and all you did is change bulbs then it is the bulbs.

[Author]

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