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Headlights failed after driving through snowstorm, I still have gauge lights, park lights, signals, and can flash (by pulling back the bar) high beam


Cyb3rst0rm

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So to preface my truck is a 1995 Extended Cab 2WD 4.0, no DRL Module (that I can find). I'm posting here not only to get help, but also so if someone else needs this info later is easily available to them as this could have caused major problems for me if it had happened at a different time.

The other day I was caught out in a nasty snowstorm and it took me about 2 and a half hours to make it the 20 or so miles home (mostly fighting my way around steep inclines, inching down them, or try to navigate corners occasionally integrating some sort of incline. I couldn't have found a much worse area to be in with a 2WD truck with no rear brakes. My high beams were on about the entire time, along with the (extremely hot in my truck) heat at full blast and the dash was getting hot, like the gauge cluster where I had my phone for GPS was uncomfortrably hot along with most of the dash though thats not entirely unusual for my truck when the heats on though this time it was worse than usual. My headlights had been on (on normal) for about 2 hours before that snowstorm started. Anywho, via a combination of luck, skill, determination, and manpower (thanks to the random dude who pushed my truck while I floored it out of a ditch) I made it home. I went to work the next day and came home and I didn't have any need to use the headlights then so I can't comment if they were working at that time but I'm going to guess not. I went to go to leave to grab some food later that night and to my disappointment my headlights would not turn on. I haven't had any luck since then. The current symptoms are:

* If the headlight switch is moved to park it functions as expected.
* When the switch is moved to the on position, it functions as if it has not been moved from park to on. Neither headlights nor high beams work, no high beam indicator on the cluster if the multiswitch is moved to high beam.
* Flash to pass (pulling back the multiswitch) still functions.

I looked up the following 2 fuse panel relay diagrahms and replaced the fuses marked in green (I've only had this truck 10 months and I replaced most of the fuses when I bought just because fuses are cheap so why not. I replaced the ones in green again yesterday). I also swapped the two large format fuses (I couldn't find spares at my local store) around since if I swapped them and the headlight fuse was bad then it would be in the fuel pump position and cause the truck to fail to start. Needless to say the truck still started and the headlights still didn't work so it wasn't that one.

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That should cover everything vaguely related to the front lighting system. So I've ruled out fuse failure. The next logical step was to replace the multifunction switch with a spare I had bought while troubleshooting a brakelight issue (which ironically, ended up just being a fuse. Go figure). With the new multifunction switch in place I had the exact same results as before, though I did note my connects were prone to coming loose easily, so I made sure when reinstalling the old switch (since one does not replace whats not actually broken) to make damn sure they were tight. One green wire was observed to have left the upper multiswitch connector, that wire has been pushed back into the connector. Google search indicates that plain green wire (with no stripe) is related to the brake lights not the headlights. No unresolved issues or defects were noted on either connector. So that ruled out the multi-function switch. My next step was looking up a wiring diagrahm for the headlights, which I found two. The first is specifically for 90 and up rangers and is from RS. The other appears to be for a 95 Explorer and is the same except for also having foglights included on the diagrahm. I'm including it because its slightly better drawn out and more detailed.

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After looking at both diagrahms it would appear that the high beams draw their power before it passes into the multiswitch. The flow of power in order is from the Hot input of the power distribution box, through the #11 20A Fuse inside of it, to the headlamp swtich, through the multifunction switch. The path for the beams from the MF switch are as follows:

HIGH BEAMS: Power goes to the #33 20A Fuse on the interior fuse panel, then to split, going to the instrument cluster high beam indicator, the DRL Module (if so equipped) and the high beam filament of each headlamp bulb.
LOW BEAMS: Power goes to the number #4 and #8 15A fuses for the LEFT (4) and RIGHT (8) headlamps respectively, then (assuming no lamp out indicator module) power flows directly to the low beam filaments.
BOTH BEAMS SHARE COMMON GROUND, ONE GROUND PER HEADLIGHT.

So if I'm understanding these diagrahms and the effects of the various vehicle components correctly the issue MUST be either the 3 position headlamp switch on the left side of steering wheel on the dash, or the wiring going to it into the multiswitch (since in this case the switch has been ruled out by swap test).

IF THE POWER WAS LOST BEFORE THE LIGHTSWITCH: The park lights, and dash lights would fail to turn on. The warning chime for lights on would also fail to function.
IF THE POWER WAS LOST AFTER DUE TO FUSE FAILURE: Only one headlight would likely be lost (and we've ruled out fuses anyways)
IF THE POWER WAS LOST AFTER HEADLAMP SWITCH BUT BEFORE THE MULTI SWTICH: This is still a possible cause, as the effect would be similar/identical to a failed switch). Issue would be either with connector or wire.
IF THE HIGH BEAM POWER WAS LOST AFTER THE MULTISWITCH: The flash to pass function would not work either, and the dash high beam indicator would most likely turn on. Possible causes would wiring, bulbs, and connectors. Single headlight failure would most likely result.
IF THE LOW BEAM POWER WAS LOST AFTER THE MULTISWITCH: Effects would be similar to observed issue but single headlight failure would be most likely. It's also unlikely given that the current behavior is identical to a switch indicating park lamps only position, and the fact the dash indicator light thinks the MF Switch is NOT in the high beam position when it is, yet functions for pull to pass.

So the following trouble shooting work has been performed:

* 1.) Replacement/verification of all applicable fuses
* 2.) Verification of MF Switch function.
* 3.) Bulb filaments verified to be intact.

So the most likely explanation is that the rapid and prolonged stress of usage heated up the three position dash switch, causing its failure when I parked my truck and turned the lights off that night (and allowed the truck to cool to the outside temperature of 12 degree rapidly). The possible causes are overheating, old age, and very possibly just mechanical failure, any of the 3 furthered by extreme incliment weather and cold. Its also possible ice shorted out a ground and blew the switch out. The other less likely cause is the wire between the multifunction switch and the dash headlight switch melted (I haven't checked for that at this time.

I'm going to the local scrap yard tomorrow to acquire a new dash headlight switch and if required new cabling connecting the two. If I'm right the headlights should function afterwards. Can anybody here find any logical failures in my troubleshooting, or possible causes for this set of symptoms that I've overlooked? I really need this truck able to drive at night, its my only ride to work.
 

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bobbywalter

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did you run straight power from the battery to the headlight low power side at the lamp? and ground to ground.?


the drl jumper isnt stressed is it?

likely heat distortion on the main headlight switch....did you unplug the main switch and jumper it there?
 

gw33gp

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I am sure someone will come in to give you more help. One thing I haven't seen in the diagrams is a relay for the head lights. It may not have one but it seems like it should. The fog lamps have a relay.
 

bobbywalter

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the main switch is why it dont have a relay. they get brittle and crack and cause bad connections over time....or from....uhhh...like my truck...spend time under water....


i hook a relay close to the headlight so i get better power that way and run the relay with the switch.
 

Cyb3rst0rm

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How do I jumper the headlight switch connector?

33431


Do I just shove a paperclip in it and bridge Pin 5 or 6 to pin 2? How do I accomplish this without blowing a fuse, melting the connector, or electroncuting myself?

(EDIT: I'm serious. I'm a computer technician and thats how I would bridge any other electrical connector to do test it. I'm just new to the piece-of-crap truck wiring business)
 
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bobbywalter

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sure.....or a jumper and some blades...or pins....

is the connector melty and brittle?
 

RonD

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Yes, flash to pass by-passes the Headlight switch, so it works even if lights are off, its powered from Maxi fuse 11 in engine fuse box, which also powers the main light switch, so that fuse is OK

So yes, when you turn on the main light switch it sends 12volt to multi-function switch which passes that 12volts to low beam fuses or high beam fuse depending on drivers setting
Flash to pass power passes thru multi-function switch as well and thru the high beam fuse, but different contacts in multi-function switch

My money would be on main light switch

To have both low and high beam contacts in the multi-function switch fail at the same time is possible, and these do share the one power wire from main light switch, history just says main light switch is more likely to be the problem, if the fuses are not
 

Cyb3rst0rm

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Ok so I just wanted to update everyone.

I went to the scrap yard today and I replaced the switch with the switch from a 2008ish era Ranger. I also discovered my trucks dash clips had all been broken or removed so you can just bend the piece of plastic that the switch is mounted to backwards and out without removing anything, it already had an aftermarket switch installed (though it looked quite old) so I'm guessing this would be the trucks 3rd light switch. My headlights are working fine now, and I also discovered I had a low beam filament out in one of my two headlight bulbs. I'm not sure if the switch blew the bulb or the bulb blew the switch. I didn't find any signs of melting or burning.

So to anyone that comes across this later, the information in this thread can probably be considered to be reliable for future troubleshooting purposes.
 

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Bulb did not blow the switch.
Switch did not blow the bulb.

coincidence

congrats on the repair
 

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