'51 Avensis 2.0 vvti C/L 7.5A fuse

[bootzey]

Hi all.

Not been here in a while (one reason for buying an Avensis), sailed through its MOT apart from needing some sill welding.

Anyway, as in the title, the 7.5 amp fuse which controls the central locking, dome light and radio/computer keeps blowing...I brought a box of 30 fuses for the process of elimination. 

Everything is fine until I drive the car. Basically, I noticed that the fuse blows when I turn sharp right. I turn left out of my drive, left at the end of the road and then when I turn right the fuse blows.

I've just gone straight out of my drive then done two circuits of the estate but all left turns and everything fine. Then on the third circuit missed the last left turn, then turn right and the fuse blew.

When standing still and ticking over I've opened each door intern, wobbled the slam switch and door umbilical tubes, bonnet switch, boot switch, messed about with the dome light whilst it's on, wobbled both fuse boxes, relays and the c/L integration unit, bounced the car with steering on full right lock and nothing happens, the fuse doesn't blow but drive, first right turn and it blows.

When I washed the car last weekend I'd used a high pressure hose end and when I first started with the sponge the alarm went off but wasn't actually armed. Might be related but the fuse was blowing three weeks before I washed it so probably not.

If I disconnect the Battery when the alarm is going off it carries on!

It's doing my head in. Any ideas anyone please?

Dave

Edited May 19, 2017 by bootzey
Addition info

[Konrad C]

That is a hard one to trace, but remove the dome light bulb or test the wiring for shorting. Also check for a loose earth connection. You may have to get access behind the dashboard. Check all the central locking system and cables.

The last time I had kept blowing the dome fuse on my old Avensis, it was a faulty dome light. I got a second hand unit, which had different internals, but looked and fitted the same. 

[bootzey]

Cheers Konrad.

Yeh, I found that thread.

It happens with the dome unit removed but the bulb is a clouded. 

Had the fuse in for 6 hours yesterday, an hour of which the car was ticking over/being revved and everything fine. Must have operated the central locking about 50 times in 6 hours. Then drove the car, turned left twice, then went very slowly round the sharp right and fuse didn't blow. Turned left again, got to a T junction, stopped, pulled away turning right and the fuse blew again.

So it's definitely a short somewhere which I'm guessing is made when the car tips down at the left side due to the right turn. I've bounced the car to try to replicate the tip but no joy so it's only when driving.

Thought there might be a known fault like something working lose or degrading. But it could be anything even something that connect to the radio/computer unit.

Trying to avoid taking the dash off but I think I have a very busy frustrating weekend ahead.

[Konrad C]

Can I add. All my electrical problems started when I was changing the coolant, and whilst opening the engine block drain bolt (yes the radiator has drain key, but I was flushing the complete system), the tool I was using touch against the alternator, blowing one of the fusible links. I had to replace the fusible link, but had problems with the dome fuse. That was with my '98 leanburn engine. 

Make sure nothing is loose in the engine bay near the electrics!

[bootzey]

Just wobbled the sat nav box in the boot and the fuse blew.

There's water sitting in the place where the wires to the box sit. The drains must be blocked and is possibly the reason I needed welding done at the rear of the sills. My drive is uphill and I reverse in so the water doesn't run off properly.

Hopefully problem will be solved...I have my weekend back!

Thanks for the input. Hope this helps someone else.

Dave