Real Time Help Needed High Beam

[Knucklehead]

Hi All,

I hoping somebody on the forum can help with lights problem on my 93' hdj80.

Was out checking them for my MOT this week and dipped beam is fine but on full beam the passanger side dip and full beam both go out.

The drivers side is fine.

Thinking it can't be a full beam bulb blown as surely that would not knock out the dip bulb as well.

Any ideas where to even begin trouble shooting would be much appreciated as I hate all things electric.

Thanks, Dave.

 

[Andy]

Relay in fuse box?

 

[Knucklehead]

Relay in fuse box?

Really clueless about electric side even after looking at EWD I have. If it was a duff relay would that not effect both driver and passanger headlights?
Currently drivers side has working dip and full beam where the passanger side dip works until i use high beam then no lights on PS while driver side has dip and high still working.

 

[Ben Stratford]

Swap bulbs from side to side and see if the problem moves too. If so get new bulbs.

 

[Knucklehead]

Swap bulbs from side to side and see if the problem moves too. If so get new bulbs.

I tried a spare high beam bulb I had but no difference. Just to be double sure I'll try swapping over the bulbs tomorrow when light and see what happens.
Would a blown high beam bulb also knock out the working dip beam bulb on that side when high turned on? Bloody typical with MOT in couple of days.

 

[Ciderman]

Relays... trace the wiring.... there's a relay, maybe even two attached to this system... 30+ year old truck, they've done a lot of work...!
Trace and check/replace the relays. they're standard issue clunk click relays, no need for Toyota OEM replacements.
Also check all earth and wiring connections for fuzzy blue corrosion on any lighting circuit connections..... may well be a simple earthing fault.

 

[Knucklehead]

Ok, so it seems I am in fact an idiot.

Should know after all these years working on the 80 to check the simple things first.

Went to check the relays as suggested and noticed there are 4 x15amp fuses for each of the headlight bulbs. Yep, high beam PS blown.

What surprises me is Toyota wiring the light circuit that if a high beam fuse goes it also takes down the dipped bulb on the same side. Would have thought better to have separate circuit so at least left with partial lighting.

Anyhow thanks for your help as usual. Now the joy that is MOT time!

Dave.

 

[Steveindar]

Relays... trace the wiring.... there's a relay, maybe even two attached to this system... 30+ year old truck, they've done a lot of work...!
Trace and check/replace the relays. they're standard issue clunk click relays, no need for Toyota OEM replacements.
Also check all earth and wiring connections for fuzzy blue corrosion on any lighting circuit connections..... may well be a simple earthing fault.

Toyota took a belts and braces approach to much of the electrics, and surprisingly it just complicated matters somewhat. Not saying it's your problem, but check the relay board behind the driver side footwell cover, right side. I've solved lighting issues by modifying the odd bit of wiring on the connections there.