Indicators not working, need help deciphering indicator circuit (pic)

[Howieau]

Hey

Im working on a mates 1990 Toyota Camry and the indicators have stopped working. The car was recently bought and the indicators didnt work. A fuse was replaced and they started working, then they just stopped working even though the new fuse is fine. Ive been following this wiring diagram for the car, and have traced 12v to the middle terminal (green/white - G-W wire) on the turn signal combination switch up on the steering column. When I turn the switch up for LH signal or RH signal the voltage on the middle terminal changes from 12 to 0 volts as the top of the Service Hint page says (see pic 2). There is no voltage on the other two terminals whether RH, LH or middle is selected. What I dont understand is shouldnt the middle wire still have 12 volts going through it and then it passes it on to the LH or RH bulbs circuits when theyre switched to. Instead the middle goes to 0 volts when LH or RH is chosen on the indicator switch on the column and the manual says this is right? Im unable to go any further with trouble shooting as I dont understand how the circuit is working. Any help is much appreciated.

P.S. All this testing is done with the Hazard lights switch turned off. Also when I choose LH or RH indicator I hear the Turn Signal Flasher click once and thats it. It doesnt click continuously if that makes any difference.



Read service tips at top of this page.

["Z" UTE]

Howieau, clean the contact points in the indicator switch on the steering column. They tend to carbon over when battery voltage is low, and you have other high drain circuits in operation..ie lights on, foot on brake, demister on, and turn signal on.

cheers Chuck.

[Howieau]

I just had a thought, where it says "The voltage should change from 12 to 0 volts when the ignition SW is set to ON and the indicator switch set to left or right". Does that mean it should change from 12volts at the middle wire(G-W) (with indicator in middle) then go to 0 when the indicator is moved to left or right signals (up and down on the stick). Or does it mean the middle wire should read 12 - 0 - 12 - 0 - 12 etc with the indicator set to left or right. If it is the second thought then that makes sense to me and it must be a faulty turn signal flasher. But if it is referring to the first thought then I am still confused as to how it works.

Any help appreciated

[wa5]

try turning your hazard flasher switch on and off a few times..... this can interfere with indicator operation at times...... if the switch doesnt go properly "off"...

also does the car have a tow bar...... and associated wiring?

[NeoNasty]

Ive had a few problems over the years with toyota blinkers in the past. Everytime its either been faulty flasher can, faulty switch at the indicator stalk (usually fixed by cleaning it out) or faulty shorted globe causing strange faults.

Just to stop you from tracing every wire and connection try those first.

[The Witzl]

also, try replacing the hazard switch with another unit from the wreckers.

[Howieau]

Replacing the turn signal flasher worked.

But now the hazard lights flash normally, and the indicators flash fast. When the hazard lights are on all bulbs work fine and flash normally, but all bulbs flash fast with indicators.
The car does have a tow ball and and plug for it. The back of the plug looks rough. How does this tie into the indicator/hazard circuit? I dont see it on the diagram?

[Mos]

Or does it mean the middle wire should read 12 - 0 - 12 - 0 - 12 etc with the indicator set to left or right.

Yes, G-W flashes with indicators when L or R or hazards are selected.

But now the hazard lights flash normally, and the indicators flash fast. When the hazard lights are on all bulbs work fine and flash normally, but all bulbs flash fast with indicators.

The flasher is designed to flash fast if it determines that a bulb is blown. The way it determines this is through the current that the bulbs draw. If a bulb blows, the current drawn is lower and the flasher senses this lower current. This is why adding extra indicator lights (such as a trailer) or using the flasher in the hazard mode - where it supplies 6 bulbs instead of 3 - does not result in a different flash rate.
The most common cause of a lower current draw while still lighting up properly is... LED indicators... Otherwise you need to check that all your bulbs are their correct rating.

The car does have a tow ball and and plug for it. The back of the plug looks rough. How does this tie into the indicator/hazard circuit? I dont see it on the diagram?

They won't be on the diagram. Think of the trailer indicators as an extra set of rear indicators - IE G-B and G-Y go to the trailer L and R indicators respectively.

Mos.