Electrical issue (Altrezza) brake causes park/dash illuminat

[TWSTD]

Ive got a strange electrical problem in my altezza. When I put my foot on the brake pedal the front park lights and all the dash lights come on (as if i had switched the park or headlights on). The rear tail lights however do NOT come on at this time - yet they come on as normal when the park / head lights are turned on via the stork.

Ive checked all the lighting fuses and even the dash fuse - all fine.
Ive Pulled and checked all park and tail light bulbs - all fine.
Ive tested without any bulbs in the park / tail / brake light sockets and still does it.

Any suggestions people?

Thanks in advance,
AL

[NZ_AE86]

Got a towbar or more importantly trailer plug wiring?

When did it start? What was the last thing you messed with!

[TWSTD]

Nup - no tow bar nor trailer wiring. Im not entirely sure when it started to be honest - couple weeks ago? Last thing i "played" with was repairing the tail lights (which use aftermarket LED clusters instead of standard bulbs). I dont think thats to blame though - as i reverted back to standard lighting to diagnose the problem and it still persisted!

Im anticipating someones going to advise me to start tracing wires... NOT looking forward to doing that LOL

[matt dunn]

Nup - no tow bar nor trailer wiring. Im not entirely sure when it started to be honest - couple weeks ago? Last thing i "played" with was repairing the tail lights (which use aftermarket LED clusters instead of standard bulbs). I dont think thats to blame though - as i reverted back to standard lighting to diagnose the problem and it still persisted!

Im anticipating someones going to advise me to start tracing wires... NOT looking forward to doing that LOL

the fault will be in the rear lights. unplug the lights and it will fix it to prove it.

usually when that happens someone has fitted a single contact bulb into a double contact holder,

like an indicator bulb, instead of a double contact bulb like a stop/tail.

[TWSTD]

Ive already tried it both with the tail/brake lights unplugged and also with the tail/brake factory bulbs back in place of my LED clusters (its a dual filament bulb) but it makes no difference at all.

[fivebob]

Have you checked the earths on the tail/brake lights?

[NZ_AE86]

When you turn the park lights on do you get the Brake and Highstop light to operate?

Very unlikely that the brake and tail wiring has been crushed somewhere and shorted together without shorting any other wires to earth or each other but it could happen.

[MAGN1T]

The earth to the stop light(s) will be missing so the current returns to earth via the park light filament of the stop/park bulb(s) then all the other park bulbs in parallel.

Steve

[NZ_AE86]

The earth to the stop light(s) will be missing so the current returns to earth via the park light filament of the stop/park bulb(s) then all the other park bulbs in parallel.

Steve

not if he has disconnected the rear lights and it still happens.

[NZ_AE86]

From memory they share a light check module which would be another place something could have gone but unless you shorted something or connected something wrong it would be unlikely.

[TWSTD]

Thanks for all the replies and suggestions guys. Please dont think im ignoring you - ive just been too flat out to even take another look at the car - hope to get onto it this week sometime though! Will post back with more results / comments then.

AL

[TWSTD]

Ok - did some more testing today. With no tail/brake lights in at all today, having a foot on the brake still makes the park lights come on and interior dash illuminate. I did notice that by holding foot on brake then turning the park lights on by the stork, the dash lights got about 20% brighter again.

Given that this is occuring without bulbs even installed in the tail/brake lights, it suggests a short further up the chain right?

I also checked the earths on both sides of the tail/brake light connector and they seem fine.

Where might this "light check module" be NZ_AE86? Ive not found or checked that.

Im a little stuck on how to go about eliminating things now.

[matt dunn]

Is there a trailer plug on the car?


The Lamp failure check unit or whatever they are labeled on an altezza,

common places on toyota's are in the rear guards, or under the dash.
Never done one specifically on an altezza myself though.

probably somewhere between the size of a pack of matches, or a pack of cigarettes,

and should be labelled as what it is for.

[NZ_AE86]

I am pretty sure they are behind the trim panel in the boot above one of the rear wheels. If you follow the wiring from the rear lights you should find it. As Matt says it should have something stamped on it to let you know what it does.

[ROBODISCO_20v]

Could be a faulty brake light switch, on the pedal?

[barryogen]

what do the boot lid lights do?

[TWSTD]

Ive just had a thought.... and I bet im right.... i dont have bootlid lights anymore - I had them shaved off... and i bet you the wires are shorting behind the trim panel!

I dont have the vehicle at present (its undergoing a manual conversion at my friendly local mechanics with the assistance of notorious B) - but when i get a chance to check it I am going to bet my first born son (who is due in 3 weeks incidentally) that thats what is causing the problem!