Electrical issues

[MozzEC]

Hi,

My daily runner, Corolla Zre152r 2008 has an issue with the headlight switch for a few weeks. It started with the dash lights not coming on when turning on the headlights. Discovered the rear driving lights were not working (brake lights ok) also. Switching the headlights on/off multiple times or giving the switch a few taps got the dash lights working - rear driving lights remained off.

Pulled covers off steering column to check headlight switch for anything obvious - nothing found. Put the covers back on and drove car with headlights on. Battery light started coming on/off at 20 second intervals. Within 5 minutes of driving the power steering failed and the lights went dim - car kept running. Stopped car, tried to start again, reds came but won't start - acted like flat battery. Left it for 30 minutes and tried again, car started, lights worked. Stopped car, tried to start again, dim lights and won't start.

Does it seem the headlight switch, battery/alternator type problems are related? Any ideas if it's the battery or alternator? Any advice much appreciated!

Cheers

[LarJammer]

None of those tests will show if there is a fault with the light switch / ignition switch. Surely replace the light switch first as you have known issues with it, maybe the other faults will be cured.

[GreenV8S]

The flat battery / won't crank over symptoms could be caused by an immobiliser fault or a problem with a main earth cable. You probably have two - one from the engine to the chassis, and the other from the chassis to the battery. A problem at any of these four connections, or a break in the cable itself, could produce an intermittent severe power loss. If your battery is anywhere near the engine, a tip which makes this side of things much more reliable is to add a third, redundant earth cable from the engine to the battery.

Some of the other problems with lights sound as if they may be caused by a fault either at the switch itself, or a connector/wire near it. However, if there is a major earth fault that could have all sorts of side effects.

[LarJammer]

Zulu 10 said:

LarJammer said:

None of those tests will show if there is a fault with the light switch / ignition switch. Surely replace the light switch first as you have known issues with it, maybe the other faults will be cured.

If the lights were switched directly by the switch, then I'd agree with you, but on this vehicle the switch simply tells an ECU what to do.
The fact the the same ECU also switches the other lights, makes me wonder whether a weak battery is resulting in power glitches when the headlights are switched on.

Hence my suggestion to check the alternator and battery, before spending money on a light switch.

Agree but the ecu doesnt know the owner is hitting the switch.

[MozzEC]

Hi all,

Thanks very much for your comments. I have a meter handy so will check this first and report back.

Cheers

[MozzEC]

Hi,

Checked prior start, voltage 12+. Checked while running with lights off, high 11's, running with lights on, lower 11's.

My concern is the problem with the alternator started after removing the steering column covers to check the headlight switch. Is this just a coincidence or could there be something else at play? Could there be a power drain somewhere that is producing the same symptoms?

Cheers

Edited by MozzEC on Sunday 17th September 09:21

[Penelope Stopit]

MozzEC said:

Hi,

My daily runner, Corolla Zre152r 2008 has an issue with the headlight switch for a few weeks. It started with the dash lights not coming on when turning on the headlights. Discovered the rear driving lights were not working (brake lights ok) also. Switching the headlights on/off multiple times or giving the switch a few taps got the dash lights working - rear driving lights remained off.

Pulled covers off steering column to check headlight switch for anything obvious - nothing found. Put the covers back on and drove car with headlights on. Battery light started coming on/off at 20 second intervals. Within 5 minutes of driving the power steering failed and the lights went dim - car kept running. Stopped car, tried to start again, reds came but won't start - acted like flat battery. Left it for 30 minutes and tried again, car started, lights worked. Stopped car, tried to start again, dim lights and won't start.

Does it seem the headlight switch, battery/alternator type problems are related? Any ideas if it's the battery or alternator? Any advice much appreciated!

Cheers

Hello
In your above post you mention It started with the dash lights not coming on when turning on the headlights, I don't think anyone above has asked you if you mean the illumination lights for the dashboard or the battery light, oil light, park brake light etc and this matters much
If you mean that the battery light etc didn't come on when turning the headlights on, the alternator relies on the battery light for it to cut in and start charging, if you have no battery light you will have no charge. It is often the case that even if there is no battery light if the engine is revved very high the Alternator will cut in and charge the battery

So, if you do mean no battery light when headlights are turned on, try revving the engine up and check to see if the voltage at the battery is now approximately 13.5 to 14.5 volts, if the Volts are now OK there is a very good chance that the headlight and battery light faults are being caused by the same problem.
You need to post back here about what you mean by dash lights not coming on