dash lights problem

[The Big Yin]

hey there i have a Trueno a 1984 model


having a problem with the dash lights


all the the emergancy lights light up

like handbrake low petrol etc etc

but none of the back lights work
for the speedo petrol or revs

any ideas?

i have the complete dash out at the minute
all the bulbs were ok except 2

the othe ones worked though so they should have lighted up

quite annoying hile driving at night i cant see what speed i am doing

[EE80Liftback]

It might be the rheostat switch (i don't have one but i guess you do) if i'm not mistaking this is "on the way to ground" coming from the bulb.

So check if you have a supply power to the bulbs (check fuse if none!) and if this is ok try to shortcut the rheosat switch.

[edit: even if the rheostat would be in series with the postive side of the bulb (i don't really grasp the diagram somewhere else on this site) you could test it by shortcutting]

[banpei]

Here you have the lightswitch diagram:

But I can't find the wiring diagram for the dash.

[Ivan141]

EE80 has it right on the money. Your rheostat (potentiometer whatever) is faulty, just fixed this on my car by taking the wire out of the connector and shorting it to the nearest groundwire I could find (on some un-used connector behind the dash cover). This way your backlights will work at full intensity, without adjustability. I'll be trying to fix mine once I put my spare switch in.

[EE80Liftback]

It's nice that the AE86 and MGB have some things in common... Makes it easier for me to diagnose electrical system faults :-)

[The Big Yin]

time to revive a dead topic

just getting round to looking at this now

what is the rheostat switch?
is it the actual switch used to turn the lights on and off?

we are stuck as to what we are looking for

[banpei]

The rheostat switch is the big round ring around the one to switch on the lights.

[The Big Yin]

banpei Wrote:The rheostat switch is the big round ring around the one to switch on the lights.

thought so

why not just call it a bloody light switch lol

[EE80Liftback]

Because it's not a light switch, it's a rheostat ;-) Rheostats are used to set how bright the light is, light switches just switch lights on or off. But then I guess you noticed that as well :-)

You can leave the rheostat switch out when it's broken which will make the dash lights work at full brightness.

[The Big Yin]

and how do you do that?

is it possable to remove the rheostat and how?