Hazards and trailer-tell-tale

Hi,

County 110 reg '85 - symptoms and what I've done below . . .

When hazard lights are turned on without the trailer attached, the dash trailer-tell-tale light flashes but the indicator light does not. (potential MOT failure).
Otherwise electrics all work fine - ie indicators when turned on cause the dash indicator light to flash etc

I replaced the trailer socket on the landy (old one rusted and gunky).

If I plug in the trailer, external trailer and landy lights work fine (note caveat below).

However with the trailer plugged in:
the dash trailer-tell-tale light remains extinguished even if I turn on the side lights.
if I turn on the hazards the dash trailer-tell-tale flashes but the dash indicator lights still do not flash
if I turn on the indicator (left or right) all external indicator lights work fine, the dash indicator light flashes as normal but the dash trailer-tell-tale flashes once and then stays extinguished.

My gut feeling is that there is an earthling problem somewhere - either that or something is miss wired (garage at last MOT played around with the electrics - long story not worth recounting - they should have left well alone - the above problem existed then - they passed it after a discussion).

Any diagnostic geniuses with ideas on where best to investigate? (I'm poised with the multimeter . . . ).

Thanks

. . . and one additional clue . .

If I unplug the hazard switch the indicators stop working entirely (ie no indicator lights come on anywhere and no sound from the flasher unit when I indicate left or right) - I wouldn't have thought that that should happen but happy to be corrected . . .

Alf111 said:

Hi,

County 110 reg '85 - symptoms and what I've done below . . .

When hazard lights are turned on without the trailer attached, the dash trailer-tell-tale light flashes but the indicator light does not. (potential MOT failure).
Otherwise electrics all work fine - ie indicators when turned on cause the dash indicator light to flash etc

Click to expand...

My '92 90 does exactly the same thing. Last MoT, the chap failed it for doing this. I protested so he checked his book, decided he was wrong and passed it.

Alf111 said:

. . . and one additional clue . .

If I unplug the hazard switch the indicators stop working entirely (ie no indicator lights come on anywhere and no sound from the flasher unit when I indicate left or right) - I wouldn't have thought that that should happen but happy to be corrected . . .

Click to expand...

The hazard switch is integral to the operation of the indicators - when the hazard switch is off, power is still fed through it to the indicator stalk. When the hazard switch is off, the stalk is bypassed and both left and right indicator circuits are connected to the flasher unit.

Thanks for the info on the hazards switch - makes sense.

The circuit diagram in my landy manual does not show show how the trailer electrics are connected into the landy. Anyone got a copy of the diagram? Also - anyone know which part of the circuit activates the dash trailer-tell-tale? The only wire on the trailer circuit that looks suitable would be the 'earth return' (trailer socket pin 3) which I'd assume provides an earth to the dash trailer-tell-tale when a trailer plug is plugged in????

And additionally - does anyone know the pin designation on the four pin flasher relay - using my multimeter it looks like

C2 - Trailer-Tell-Tale
31 - Earth
49 - +v supplied by hazzard switch or alternatively indicators when ignition on
49a - earthed when either hazzards or indicator turned on - ie +v out to external flasher bulbs

is that correct??

I've been sent this - posting it here as it may prove useful to others . . .