Rear Brake Light Problem

[piketail]

Hi Folks

A newbie here. I have a venerable 1996 RAV4 which has been utterly reliable. I have a problem with the rear lights which I hope someone can help with.

1. Both rear parking lights are on max brightness when switched on.

2. The nearside brake light does not work, but the offside one does. A blown bulb has been replaced.

I presume it is a wiring fault, but how does one go about resolving the cause or location?

Thanks for any advice.

[Guest]

I will hazard a guess that there is a poor earth to the light, this can show up in a wide variety of ways such as rear (red) light flashing when indicating, try and find the wire that is connected to the chassis and make sure that the connections are clean and has a good connection to the chassis (a bit of wire wool can clean these up) secondly take the bulb out and verify the contacts in the holder are clean - make sure the power is off when you check these, might be also worth checking the fuses.

My starter for 10, I am sure that others will be along with other ideas soon.

Gus

[Parts-King]

Ive seen 380 bulbs forced in the wrong way round. You put the sidelights on and it displays brake lights. That would be worth looking at too

Kingo

[pmb]

I recently replaced a rear brake/tail light on a berlingo as the brake light had blown. Some days later I noticed that the tail light wasn't working. Turned out I hadn't seated the bulb correctly. I should have checked both lights when I replaced the bulb.

[piketail]

Hi Guys

Impressed by the speed of responses. Thanks for the comments.

Re the bulb, it is the right way round, quite hard to get the offsets wrong. And clearly the base contacts are OK because it lights on parking.

As a supplementary question, does anyone have access to the wiring diagram and can identify the colourway for the brake lead? And is it possible to get into the bulb socket if it is necessary to run a duplicate lead to the brake switch?

Thanks

Walter

[Tech01]

If really stumped, just run a single cable across to the other brake light (they're both on the same circuit). Don't bother to take it back to the brake light switch.

Chris

[piketail]

Chris

Thanks. That sounds like a great idea. Now all I need to establish is which of the two possible cables is the brake one. And how to get into the actual socket non-destructively. More suggestions please.

Walter

[Tech01]

Walter

I don't have a circuit diagram for a 1996 model: earliest one I have is 2001 - but Toyota haven't much changed the wiring of basics like stop lights. Diagram I have shows feed to stop lights coming from brake pedal switch, and then to two noise suppressors (one for each brake-light/high-level stop-light) and thence to the stop-lights. The noise suppressors are usually small plastic blocks (about 2x1cm) wired in series with the relevant lead, often plus an earth connection bolted to body. (It's possible one of these has gone on yours: test them by simply shorting each one out and see if anything then works.)

As an alternative to the above, you can non-destructively find out which of the wires to the rear light is the brake light by simply spearing one cable at a time with a sewing needle, and putting a test-lamp (or meter) between the needle and ground. If you can find the brake-live wire on your good light, look for the same colour wire on the duff one, and join these.

If the same colour doesn't turn up on the duff side, then again needle-spear a chosen cable, and this time connect a +12v supply to it (and -ve to body) and see if the brake filament lights up. If it does, you've got the right cable - join it to the other one.

My 2001 circuit diagram shows earth/ground connections to the brake lights as white-black, and the brake light feed as green, green-red, etc. Perhaps similar on yours. Probably best to just go for needle-testing!

Hope helpful.

Chris

[piketail]

Chris

That sounds really useful. I'll try that approach. Fingers crossed.

Thanks

Walter