Headlamp Issue - Cutting Out

Okay, first I'll start off by saying I'm about 90% certian it's the switch, I just wanted to see if anybody else has had this particular issue.

When driving with the lights on they will turn themselves off, back on, back off, etc, with no pattern (no bumps, gently tugging on the switch will not keeep them on, different positions of rotation have no effect), this is only the headlamp circuit, and only happens after I've been running them for maybe twenty minutes or more. If I turn the switch off, then back on they will usually come back up (then start cutting out again very soon), but sometimes they will refuse and it takes a couple cycles.

The switch feels okay (i.e., when you pull the knob out everything feels proper), that is the only issue, the instrument lamps dim though the whole rotation how they should. I replaced the switch a little over a year ago (different problem, physical breakage in the aging switch).

This weekend I plan to replace the switch and take a good look at the wiring right up at the switch, I do remember it being quite warm when I replaced the switch last year (emergency job, did it in a parking lot at night), so there is a concern there.

Okay..last part..I would like to get a headlamp harness, I feel that this failure was most likely caused by too much draw on the switch (H4 lamps), anybody know a good place to get this?

Thanks,
Sequoia

The headlight switch incorporates a circuit breaker, and that's what's cutting out. I went through that with my old full-size Cherokee.

Painless Wiring may have a harness, but it's really easy to make up. Basically you just need a relay and a couple of headlight sockets, and some 12 gage wire.

headlamp rewire

atuozone has the heavy duty lamp sockets needed for what you want. those 2 relays and some heavy wire will do the trick. check previous post concerning rewireing headlamps. somebody gave great diagram. :wave:

When I replaced my grill surround I noticed that my headlamps were dimming. I played with the plug that the bulp connects to and found the ground was loose, causing the headlamp to brighten, dim, or go out completely....the ground wire going into the actual socket that is....

I've actually thought of making my own loom as well, and might still do that depending on a few things (such as how much the pre-made sets cost, if it's not that much mroe than raw materials laziness will prevail ). I do have one question though.

I forget how to find amerage right. My lamps are 85w/100w if I remember right (yes, they're brighter than stock), I may go the next step in high beam brightness..perhaps...

Anyway, I'd like to calculate the draw, in amps, of each light on each setting so I can choose the best size wire (and not get it too much bigger than necessary, I have precious little space under that hood!).

Sequoia

I just made up a new harness when I did the H4 conversion. At the same time I added 2 relays 1 each for high and low beam.

I used 12GA wire from the relays to the headlights. The relays make the headlights brighter, safer, and more reliable. I feel better knowing that all the voltage and AMP's are not going through a 14 year old switch. I spliced into the wiring harness forward of the large connector by the air box and mounted the relays on the fender under the ballast resistor. To feed the new relays I used 12GA wire with an inline 30AMP fuse from the battery.

Here is a diagram to help explain it all.

Lunatic728 said:

I just made up a new harness when I did the H4 conversion. At the same time I added 2 relays 1 each for high and low beam.

I used 12GA wire from the relays to the headlights. The relays make the headlights brighter, safer, and more reliable. I feel better knowing that all the voltage and AMP's are not going through a 14 year old switch. I spliced into the wiring harness forward of the large connector by the air box and mounted the relays on the fender under the ballast resistor. To feed the new relays I used 12GA wire with an inline 30AMP fuse from the battery.

Here is a diagram to help explain it all.

Click to expand...

I noticed in the diagram that you only have one hot wire feeding both bulbs.If the top bulb in the diagram blows do both lights go out? Looks like a old set of christmas lights where if one bulb blows they all go out.
Don,t know if that is "series or paraell"
Just asking?
Wayne

Wayne,
You're correct. That schematic is not quite right. Contact 30 should be going directly to both bulbs. Contact 86 should de driven by the wire that originally went to the bulb socket(from the stock harness). And as stated, you would duplicate it for the hi and lo beams.


Yo G,

Amps = Watts / Volts (e.g. 8.3A=100W/12V )


Twelve(12) AWG is a good guage for this application -- as long as you're not running a couple hundred feet of wire.

Yep, design flaw in the diagram. On my 90' the power for the pass. side headlight is spliced into the headlight connector on the driverside. I just didn't know how make the arc over the ground wire with the paint program I was using.

GSequoia said:

I forget how to find amerage right. My lamps are 85w/100w if I remember right (yes, they're brighter than stock), I may go the next step in high beam brightness..perhaps...

Click to expand...

85/100 on stock wiring? Ouch...... you *REALLY* need to build a relayed harness!

The simple equation is watts = amps * volts. Yeah, I know..... but it's close enough for government work.

I'd allow 10 amps per headlight, so you'll need at least 20 amp relays, and fuses to match.

I built mine just before the Fall Fling after burning up a switch and shorting out an alternator. I have 55/110 bulbs, and it smoked after running 3 hours on the high beams.

Edit: There is another possibility. The harness connector behind the airbox is known for corrosion. I lost the front marker lamps and low beams before I figured out what was wrong.

I think you're just overloading the circuit breaker in the light switch. You probably don't have any option but to re-wire if you want to run headlights that are almost double the wattage of OEM.

Safety Comment:

I find bright lights very offensive and unsafe for because of the vision difficulty it creates for the oncomming driver. If you're running them on the street, it's not very responsible. I've used 50/100 lamps in the past which do give you a legal and safe low beam.

PaulJ said:

I think you're just overloading the circuit breaker in the light switch...

Click to expand...

The only thing I find odd about that is the fact that this just started happening, I've had the lamps for a couple years now. Not saying that I won't be building a harness, I've been meaning to for those same two years

PaulJ said:

I find bright lights very offensive and unsafe for because of the vision difficulty it creates for the oncomming driver...

Click to expand...

I know what you're saying on that. I'm more anal that you could possibly believe when it comes to aiming them lights, I even make friends in little cars make sure I don't blind them. High wattage lamps are okay as long as you aim them properly, once you do that they make a big difference in the quality of light you throw.

Sequoia

Could be that the near overload over a long period of time has taken its tool on that circuit breaker. I've had a circuit breaker in my house exhibit this.