headlights randomly stopped working

[86d50]

Yes I checked the bulbs it's not the fuses.

[camoit]

So does anything happen when you wiggle the switch? Or is it come on and off when hitting bumps? Need a bit more info. It could be the switch getting hot, could be a bad plug, loose wire, bad body ground, but I would guess it's the high beam switch.

[lush90]

Also, is it both high and low beams?

[86d50]

Iwent out yesterday and started the truck. Turned in my lights not on but so the dash light would come on and it worked fine. However when I switched them to turn on my headlights nothing no low or high beams.

[pennyman1]

Check the tension on the headlight fuse clips - over time they lose tension and the lights quit working. Also check the grounds from the headlights to ground. Do the rest of the lights come on on the outside of the truck?

[86d50]

all the other lights work the headlights just won't come on when its really cold

[suresight]

Hey guys, I'm having a similar problem now.

1. Running lights and dash lights work when switched on
2. Low beams DON'T work
3. High beams do work
4. Fuses are all ok
5. Opened the headlight relay (Mitsubishi MB046436 Nippondenso 056700-3060) and the switches are functioning properly

Any advice on next steps would be great guys.

Thanks!

[geezer101]

Check power out of the relays to the low beams. Just because you can hear the relays kick on doesn't mean the contacts aren't roasted. I'd be putting even odds on 86d50's truck having a similar issue. The relay is almost dead but as it warms up, it makes contact. Bigger alternator time all round methinks, add independent relay and headlight harnesses so the circuits are getting full current which will make the headlights more efficient and take strain off the rest of the electrical system. When you're ready for a H4 halogen upgrade, all the work is already done :)

[suresight]

Do you know which alternator would suffice? My 4d55 has the oil connection on the back which has always been a problem from the beginning. I definitely agree it is under powered, the wipers are in slow mo when the lights are on.

[geezer101]

Need one of the diesel gurus to step in on this one. I have seen the oil housing on the backs of the 4D55/56 alternators and it looks like one of the dodgiest/scary ideas Mitsubishi has used.

[pennyman1]

the diesel alternators have a vacuum pump on the back for the power brake booster, as there is no vacuum off the motor.

[geezer101]

the diesel alternators have a vacuum pump on the back for the power brake booster, as there is no vacuum off the motor.

Well I learned sumpin :) Actually I learned 2 things, maybe 3...(like offering my valuable input when I probably shouldn't lol)