head light problem, urgent help needed

[snowwolf]

Hi all, I need so help asap, my fzj80 just failed its MOT test on a headlight problem.

you have both headlights on, on normal low beam, and as soon as you put the high beam on, the right handside (as you look from front of car) headlight goes out with no low beam or high beam lights working on that side, but the left handside both high and low beams are lit up, as soon as you take it off of high beam, then both the low beams work,

I hope I have explained it ok.

The reason I need to get this sorted, is because the MOT testing place will charge me another £40 for a retest, so have 24 hours to get the problem sorted....hope you can help!

PS I have taken off all the bulb connections and can't find anything wronge

 

[eldgenb]

I would replace the headlight relay in the fuse panel 1st.(start with the cheap stuff) If that did not work I would think it was the headlight switch on the steering column, to test that I would use a multimeter to see if your switch is functioning properly. I don't know of any common problems that would cause this, I think CruiserDan would be the pro at this one.

 

[snowwolf]

Thanks for the reply eldgenb..... I have just rechecked all the bulbs and even swapped them from one to to the other, but still have the same fault, I was hoping it was going to swap the fault to the other side, but it didn't :-(


I will have to order a new relay from local Toyota

 

[Rainy Day FZJ]

Most of the relays are of the same size in your rig, grab one out of a know good one and plug it to make sure on your diagnosis, before you plunk down your hard earned pounds.

 

[snowwolf]

Hi all..... I went back out on truck to see if I could remove the relays, it was then I noticed 4 fuses, and the four fuses are for the left and right high and low beam, I found one of them blown!!!! yipeeeeee!!!! changed the fuse and all was cured.

Its just so odd, that it would cause such a wierd fault, why would putting the high beam on, cause the low beam on one side to go out???

Ah well, I am happy now, so if anyone else has headlight problems, check them four fuses

 

[Doc]

Yes, there are fuses both under the dash inside the cabin, and under the hood, in the engine bay. Check them all!

Glad it was an easy fix for you.

 

[snowwolf]

Thanks Doc....me happy too, and saved myself another £40 retest fee

 

[mot]

... because the MOT testing place will charge me another £40 for a retest...

You got it confused, I only charge ￥40.

Glad you got it figured out!

Mot

 

[Mike S]

...Its just so odd, that it would cause such a wierd fault, why would putting the high beam on, cause the low beam on one side to go out???

Maybe a fault in the flux modulator circuit.

M

 

[MTPCRUISER]

Glad to hear that you sorted it out. The reason that the low beam went out is that the high and low beams on most lights are different bulbs or at least different filaments. When you activate the high beams, it turns off the low beams and turns on the high. I just learned this when my high beams failed. The lows worked fine, but corrosion on the switch prevented the highs from coming on. If I turned on the highs, the lows went out. Cleaned up the contacts and all is well.

 

[MARLIN375]

Its just so odd, that it would cause such a wierd fault, why would putting the high beam on, cause the low beam on one side to go out???

Try putting a test light on your bulb leads....when the bulb is off the lead is hot and when the bulb is on the lead is cold....... ........scratched my head for a long time on this one while trying to wire my driving lights up to my high-beam switch.

eventually got some help from expert automotive electrical friend............his explanation got complicated but had something to do with the switch being the point that closed the ground circuit and tripped the relay.

I did get my lights working properly (although the dash switch cannot be lit and the driving lights come on when you turn off your headlights, with the dash switch on)

I still dont know how the bulb comes on........but i do know if you let the smoke out of the wire you have done something wrong.