Strange electric problem on Gen1 Avensis

[Ehetyz]

I have a peculiar issue on my 1999 1.6 sedan Avensis. The electronics system of the car is acting up and powering things in the car in seemingly random ways.

I'll start from the beginning, about two weeks ago I noticed the parking lights would not shut down the way they're supposed to when turning off the engine and removing the key. Flicking the light switch or turning the key repeatedly made no difference. I checked the fuses but they were all fine. Then, during the day, the problem disappeared, then reappeared again momentarily later on a few occasions - and again went away without a trace.

Then, this weekend, after sitting for two days, I found the Battery had drained. Had to pushstart the car and took it to a repair shop, explained what had happened and told them about the problem with the lights. They did a troubleshoot on the car, but they found no fault in the system (the lights didn't act up that time). Took the car back home and unplugged the tail light fuse (I was informed this controlled the parking lights) just in case.

Yesterday I went to the car... And the stereo was somehow on. On my Avensis it's only supposed to get power when the key is in ignition and power turned on. Tried to start the car, then shut it down. The stereo didn't shut down, but it was being powered in intervals, something like 4 seconds of power, then shutdown, then back on, etc. At that point I just threw my hands in the air and unplugged the Battery.

Today the stereo is no longer bugging out - but I dread what goes crazy next.

 

I was originally thinking the problem might be with the light switch or light relays, but since it's putting power into the stereo system as well, I think I can at least rule out the switch. Has anyone else had this kind of "haunting" with their car, and what could cause this kind of thing?

 

 

[ents]

I think that ignition switch causes your problems.

[Konrad C]

19 hours ago, ents said:

I think that ignition switch causes your problems.

I agree with Henri. Try changing the ignition switch in the steering column. It is straight forward to change. I changed mine in around 15 minutes. Just have the right size crosshead screwdrivers.

Here are some topics on the switch:

 

 

 

My post also highlights that there are switches that look identical but the connections are different. Beware of buying the "wrong" switch. That is why I got mine from Toyota.

[Ehetyz]

Thank you, I'll look into the ignition switch then. Will have to find out which of the switches corresponds with my model - the domestic general parts dealer listed three possible codes, so I'll probably have to get in touch with Toyota service for that.

This might be confirmation bias, but glancing through the ignition threads it seems that for a lot of people the problems popped up during warm weather, which is what's been happening to me as well.

[Konrad C]

I have the Haynes manual which covers the Mk1 Avensis and also has the wiring schematics. It is a UK publication. 

Check the earthing for loose connections or corrosion.