Archived Lights not working

[HWestfall]

I am having with the front lights on my 02 3500. Last night the left head light quit working on low beam. I went into a parking lot it was working, when I went to leave the left light was out so I went to Wal Mart and got a new bulb. That didn't work so I got a probe to check the plug, both the outside sockets are hot on low beam but the bulb won't light. The High beam works. Two years ago at May Madness the driving/ fog lights quit. I have installed new bulbs and a new light switch thinking it may have been that. No lights both of the wires to those bulbs are hot. :{ HELP I'm running out of lights HWestfall















02,3500,Laramie, 4x4, 6sp, Patriot Blue, Pac-Brake,Isspro Gauges,Chrome Brush Guard, Dee-Zee Running Boards, Stainless Wheel & Side Trim,KC Dayliters, Sprayin Bed Liner, XM, 70 gal Aux. Tank, FASS Plat. Trans Pump, Amsoil Thruout with Double By Pass Filters, Smarty, Stock Tail Gate Cut Down for 5th Wheel



















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[B.G. Smith]

The head lights have +12 volts to them at all times, they are turned on by grounding the -side of the circuit. Right and left head lights have seperate circuit and are operated through relays in the PDC, may be the relay. bg

 

[HWestfall]

OK I have checked the fuses but not the relays for the headlight, Ihave the fog/road lights they are good but the lights still don't work. Will check head light in the morning. Harry

 

[HWestfall]

Checked replaced relay, Headlight switch & socket still no light. Help Harry

 

[Chief USA]

Checked replaced relay, Headlight switch & socket still no light. Help Harry

Harry, the high/low beam/turn signal "stalk switch" on these trucks is a known problem. Mine does this on occasion especially if I have not driven the truck at night for a long period of time. Sometimes I loose the headlights altogether or just the high or low beam. I just cycle the high/low beam "stalk switch" several times and this brings back the head lights.



The other issue is if you have the headlight relay (direct to battery APC conversion harness which they no longer make) harness installed, the relays are cheap and stick if you have the fog lights on along with the head lights and shift to high beam and then try to cycle back to low beam. The headlights will become stuck on high beam. Turning off the fog lights and recycling the high/low beams again will bring back the low beams. My truck does this as well. I have this harness installed.



If by chance you have this or a similar harness installed, these relays should work as replacement relays if yours are bad:



suvlights.com Relay 4 pin (30, 85, 86, 87 terminals) 12 volt 30 amp Song Chuan (part# 804-1A-C

 

[B.G. Smith]

There is a relay in the PDC that takes out the fog/driving lights when high beams are switched on, that could be stuck causing the fog lights to not work. I believe it is labeled "security relay". I have a 99 FSM but I have a hard time reading the electrical scchematics. bg

 

[PBJ2500CTD]

HWestfall,

Looking at the 02 schematic, and taking the information you have given (and assuming you do not have the quad headlamps):

1. Left headlamp low beam only - inop
   • Symptom
2. Both high beams work
   • Fuses B (Right Headlamp) & C (Left Headlamp) in PDC OK
   • Multi-function switch operating as designed
   • Headlamp switch operating as designed
3. Changing the left bulb did not fix
   • Is the new bulb good? Visual check of the element may not detect a defective element connection. Do an ohm check or try it in the right side.
   • Is the socket making good contact with the bulb contacts - or has the connector spread out - wiggle and twist on the wires to see if the low beam flashes or comes on.
   • Joint Connection 1 in the PDC (VT/WT wire)
   • S106 splice bad

Only socket A in the headlamp plug should be hot at all times when both headlamps are disconnected; you will get a potential (12 vdc) through the elements of the opposite bulb if it is not disconnected from the circuit.