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87 low beams dim and high beam indicator always on


travis

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My high beams seem fine but my low beams are very dim. Also my high beam indicator is always on when headlights are on. I checked and cleaned multi switch or turn signal hi low beam switch witch ever one you want call it checked all connections and grounds. All seem good. Checked volts on light plug and there's 12 volts on both high and low wires when high beams are on. Switch to low beams and drops to 3.5 on low beam. Should it b 12 volts on low beam also? Like I said I took multi switch apart and cleaned all contacts and put back together. Also did same with light switch itself. Any info would be great. Not the best at wiring stuff. Lol
 


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It seriously sounds like a fractured (not quite broken yet) ground. But the high and low beams share a single ground wire.

Yes, should be 12v (or close) on whichever line is active. There should be nothing on the other line.

I'd check the ground on each bulb from the positive of the battery.

The 3.5 volts your seeing is the difference of potential from the wire connect to the red lead on your volt-meter to the black line. It means there is high resistance on the ground line or there is actually voltage present on it.

I'd say either a wire is almost broken or you need a replacement multi-function switch. (The one in the column.) It should be noted that I've seen the connector to that switch melt and cause some weird issues too.
 
travis

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I thought it sounded like the multi switch. Plug in and wires look good and clean. No melting or hot spots at all. Is there any way to test the multi switch? Thanks alot. Would the high low beam relay have anything to do with it?
 
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Spott

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You don't have any relays in the headlight circuit on a 1st gen ranger.

You can test the multifunction switch, measure the resistance (ohms) between the power-in pin and the low-beam-out pin. It should be close to zero.
 
Explorin94

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I agree with Senornoob. You have a bad ground.
 
travis

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Alrighty. I tinkered with it today and now I'm super confused. If I unhook wiring harness on fender well everything works as should through volt meter. So I'm pretty sure that rules out any problem in cab wiring. So I unhooked the high beam wires from headlights and dims work as should. But there's juice coming through high beam terminal on lights on both sides. Mind you this is with high beam feed wire completely unplugged from lights. I've tried a couple different bulbs and all the same ruling out a problem with bulbs. I'm kinda at a loss here. I'm pretty mechanically inclined but wiring isn't my strong point. Can anyone explain what's going on with it or any ideas? Would I b better off just getting a upgraded heavy duty headlight wiring harness like from lmc and go that way?And would that eliminate the problem? I tried to explain it the best I could. Any questions just ask. Thanks
 
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travis said:
Alrighty. I tinkered with it today and now I'm super confused. If I unhook wiring harness on fender well everything works as should through volt meter. So I'm pretty sure that rules out any problem in cab wiring. So I unhooked the high beam wires from headlights and dims work as should. But there's juice coming through high beam terminal on lights on both sides. Mind you this is with high beam feed wire completely unplugged from lights. I've tried a couple different bulbs and all the same ruling out a problem with bulbs. I'm kinda at a loss here. I'm pretty mechanically inclined but wiring isn't my strong point. Can anyone explain what's going on with it or any ideas? Would I b better off just getting a upgraded heavy duty headlight wiring harness like from lmc and go that way?And would that eliminate the problem? I tried to explain it the best I could. Any questions just ask. Thanks
Click to expand...
You have a bad ground... Like everyone said.

Run a temporary ground wire from the battery to the headlight plug and you'll see.
 
travis

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Did that. Same thing!!
 
Ranger302Boss

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That happends to me on 85 ranger. Was the yellow headlight. I dont know how, but the bulb twist and make a bridge. You must take it off. And change the plug if damaged.
 
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