hiya.. 1988 basic 4x4 truck, here is my problems;
been beating my head on the hood over this strange problem, maybe someone else has had this happen...
the headlights are new, I thought new ones would cure it...
the passengers side headlight works fine, high and lo beam.
the drivers side, in low beam is dimmer than the passangers side, and when you flick the high beams on, the drivers side light goes ALMOST [not quite] out. passangers side, functions perfectly...

I swapped the relay, replaced fuses, checked as much wire as i can reach.
no luck.

for one breif mimute it WORKED, I was thinking goodie, I fixed it somehow...

I moved the truck 10 feet and tried the lights and its back to one weak one one bright one again.

my first thought was "screw it, wire up a new headlight system" but this cant be a hard problem... I'm just not looking in the right spot yet...

[besides... I dont realy know how to wire up a new headlight system... yet ]

to fix it it I figured [wrong] "I'll wire both lights on one plug.. thatll work!"
haha no it doesnt.. joke on me.

or maybe I didnt do that right either.

the headlight has 3 prongs to plug wires to... is two hot and one a ground or.... what?

I'm still doing searches for tidbits of answers but I havent seen anyone with a similar problem...

one thread said clean the stearing colum switch contacts, but the passangers side works fine.... does that switch have seperate contacts for right and left?

any suggestions?

 

first u should try checking your voltage with a multimeter. make sure u have a good ground on the dimming light. maybe check the connections on ur voltage regualtor. i dont think the contacts in the column would do to much cause it swtiches one relay for both lights.make sure the connections right at the plug for the light are ok.

 

ack! I put this in the wrong forum.... this aint for 88s!
LOL

thanks for the input anyow!

 

Not sure if'n you'll be reading this but, I would think a ground to be at fault.
Have you tried grounding out each light via its own ground?

I suck at puters.... but here goes.

G ground frame or body
------ wire
O= ring connects wire on one end to screw to ground on the other.
< < bullit plug, Unplugs and can be used in harsh invironments.




G O=----------------< <------------------------G on HL wires as close to HL plug as possible.

There is a write up on this site somewhere, on how to really get some good light from ones lights
I think it also has a link to buy a new 12ga wire lighting loom that plugs into your old loom ( yes actual plug and play) as activation for the new relays about $ 50.00 I think??
?? Daniel stern lighting ??
good luck
VR
Repo

 

ok dumb question of the day #2
lol

which prongs on the headlight are the grounds? there is one on the top - a left/ and a right\
thus... |-|
sorta.

I'll assume the left ans tight headlamp are not left and right, but can be either.
I tald the sales guy I needed both headlights for an 88 and he handed me 2 lights with the same part #..
so I'll assume..

I'm learning as I go...

 

the ground is the one on top. _-_ when u look at the plug like that

 

thanks...
I tested the prongs with a test light, on the good side with low and high beams on...

the top prong and one side prong has power to it on high beam and the 2 "side" prongs ( | | ) have power in them on low beam... and the top (ground as you say) has no power to it.

I have another truck same yr, identical to this one that is "intact", I put a battery in it and tested its lights.. they work fine.
so I swapped out the steering colum cluster (lights turns WW ect) and the relay under the hood for the headlights...

satill has the same problem so i am going to guess those parts are not the problem.



I'm going to try to hook an aux ground to it in a while... I'll keep ya posted.

oh, and now my 4 ways wont work, the flasher buzzes, but I think thats not related to this headlight thing as the flashers were working after this headlight problem began...

 

This might sound dumb, but if you haven't, try cleaning the contacts. Also check for wires that may have been cut somehow, even the slightest bit.

 

yup, I cleaned all the contacts i can find to clean...

I was just checking the good side to get a feel for what its doing, as it is working right,...
low beam, the - post has no power, and both | | posts have power.

switch to high beams, the left (sitting in truck facing forward) |prong has power, and the top prong - has a very weak power that barely lights the test light. the right prong | is "dead".

the drivers side doesnt do that.

on low beam you have power in both | | prongs and a dead - prong.
on HI, however, both | | prongs are "dead" and the top - prong has barely enoung juice to light the test light [and the headlight is very very dim]

so there is a difference in where the power is going when you side by side each light...

if you guys can make sense of that discription.... HELP!!



I even put in new fuses... the old ones were 15 A (beside the relay) So I put in 2 new 15s.

I'm wondering now if it isnt that fuse block, because nothing I do can get the horn to work... and the horn fuse is right beside the headlight fuse, in that block in the innner fender.

remember in the first post I said;
it mighta had somethin to do with continuously messing with that block!

it looks clean, but when it stops raining again I am going to tripple check the wires and plugs.

seems to me the right headlight isnt getting sufficient power...

 

it quit raining for a few min....
if I run a jumper from the + side of the battery to the right | prong on the drivers side [the dim one] it fixes the problem... I have matching low beams and matching high beams....

but then you tun off the lights on the column and the headlight low beams stay on....
ya know I really hate cars... lol

anyhow.. if that makes any difference in guessing where the problem is.

the fuse block looks clean, the fuse contacts are clean.

 

I got it to work ok now... dont ask me how.
I cleaned AGAIN and replaced all the fuese with new ones AGAIN and cleaned everything with a brush and contact cleaner.... again.

both sides work as they should, for now....
but not finding the "problem" just makes me believe it will come back.

lol

thanks for the input i learned more than I knew before about how works your headlights...

 

wow i hope i dont have that much trubble i need to fix the high beems on my truck too. the low beams work fine and i can pull the lever and flash the high beams but whtn i push foward to lock on high beams the lights go off. i guess its probably the switch in the collom.(i hope) because i have 2 extra colloms

 

those extra trucks sitting around come in handy dont they?

 

if u had a tiny bit of power out of the top terminal ( -) then u might have a bare spot on ur wire that shorting against ur positive. but the terminals ( _ _ ) are both hot with lowbeams but only one if hot while the high beams are on

 

i dont have any extra trucks sitting around(i wish :cry: ) but my turck came with a lot of parts and i have one whole collom and one of the control lever setups. (i guess the owner before me had problems too)

 

Forgive me for 'hijacking', but I've been doing my best to read around for an answer before posting a possibly redundant question...
************************************************** ***************
I have a similar dilemma on my 87 runner. I understand how the circuits work; the headlight switch/relay supplies B+ to the common on each headlight, and the HI/LO/FLASH provides a ground for one filament or the other.
Somewhere in the harness across the front of the truck, the three wires going to each headlight "fan-out" from a common set of three wires that plug into the fuse block assembly next to the battery. My LO beam circuit is broken somewhere in there between the fuse block and the fan-out.
Does anyone know WHERE in the harness up there the fanout occurs? I'd rather fix it than replace the headlight harness. I have a FSM but it does not show harness details. I was hoping someone has had the opportunity to open one up.

 

Might be easier to bypass most of the headlight wiring:
- http://www.4crawler.com/4x4/CheapTri...#WiringHarness

 

Toyota headlights are weird. No doubt. Here is the hint. The headlight ckt switches the GROUND! check your grounds and you'll probably get it. You are leaking current back through the other headlight. On my duece (MR2) some joker had swapped in a headlight socket with the high-low switched. I chased that problem for about an hour. check for a "custom" socket wiring job.

 

I JUST solved a similar problem this weekend on my 88. Lost my low beams, but switches ok.
Here's the deal: The B+ and the two grounding circuits (one for HI and one for LO) come from the switches thru the harness, out the right front fender well, up under the relay block. There, they transition in a plug-connector. You'll see the HI beams are a red wire with green trace, and LO is red with yellow. Red with black is common for right, and red/white is common for left. HOW does this ONE wire coming from the fuse block plug get to TWO headlights? The wiring FANS out in the section of harness behind the BATTERY. BAD NEWS. They strip the wires, put a crimp on connector, and tape them up. So, over 20 years, the juices leach in there, corrode the nekked wiring and you develop a bad/intermittent/no connection. SO, you gotta do some open heart surgery. Remove the battery, and the windshield washer tank. Then take off the tape from where the right headlight wires come from the harness, toward the direction of the radiator. about a foot. Then take off the corrugated plastic cover. Then untape it until you discover those wretched splices. Be prepared with a good soldering iron, some paste flux, some extra 14g hookup wire, heat shrink tubing, vinyl tape. I had to cut back about three inches of wiring to get into clean copper so it would tin with solder. Re-do your splices, get a GOOD solder connection, put heat shrink on them, and do a fresh tape up job. My apolgies that all i have are 'before' pictures, my camera battery died on the job. This hopefully will show you the location of the potential trouble. Good Luck.