Dash Lights Dim And Side Lights Come On When I Brake

[Big Badger]

Hello All,

Just thought I would share this 'get out of jail' solution for a strange problem that I had.

I have a Toyota Avensis T180 2006. When I touched the brake pedal the dash board
light dimmed, the 'lights on' light came on on the dash and the side lights
came on. They would flicker on and off and sometimes pulse in an almost regular
way. If I turned my side lights on all this disappeared and all systems seemed
to be working fine.

A few months ago I had replaced my rear light bulbs (by the
way if these BOTH go then all your auto braking warning lights go on VSC etc so
before you go spending a shed load of cash on diagnosing brake problems just
get someone to stand behind the car and check your brake bulbs are working) and
snapped off a locating tang so the bulb holder rattles a little. I wondered
whether this had caused any chafing so a short was occurring between the brake
light circuit and the side light circuit.

All wiring looked OK, so in desperation I took out the dual
filament (21W/5W) bulb and checked resistance between the two soldered
connections to see if there was a straight short there and at 0.2 ohms (contact
resistance) there was. I checked this against a spare bulb which had about 13
ohms between the two connections. So the bulb had failed in a way I have never
seen before and the lighting circuit was getting power through the bulb from
the braking filament.

Changed the bulb with a spare one from my store of 'I will
keep that as I will need it sometime' parts and all is good again.

Hurray! Cost: £0.00

Hope this helps.

Cheers,

Large Badger

[avensis rob]

seen this before, wrong bulb fitted causing cluster sbriging

0.2 ohms is multimeter lead resistance aka open circuit aka no continuity

this is due to your stop/tail bulb 2x soldered connections being separate poles for each filament inside the bulb and the body of the bulb is the negative.

another bulb that looks the same is a 2 contact single element that does not have neg at body of bulb

not uncommon for people to buy what they think looks like correct bulb and wonder why side lights come on with brake light

the moral of the story is read the operators manual lol