I need to replace the alternator on my ATD as it is giving 11v at idle

How do I slacken off the tensioning pulley?

Hi Jamlip

What is the output at say 1500-2000 rpm?

Steve

Idle is what... 900 rpm?

Obviously above idle I'm getting a higher load, but I still want to replace the alternator before it gets so knackered that I find myself sat on the roadside without any lights or windscreen wipers.

No-one ever done this?

Is the battery light on when the ignition is turned on?

Just checked, and no.

I've had someone check the battery and it's giving 11v at idle. It's obviously giving a lot more as the revs go up, but sometimes I leave the car idling for a long time, like on shoots where we use the car as a generator, or at night with the headlamps on to provide a bit of light as you work, or even just to stay warm in. I've had it go flat a number of times now, and also on several occasions when it was being driven afterwards (scary - the power steering gets really, really heavy).

As far as I can work out, the belt is held tight by a tensioning wheel on a (hydraulic?) arm, but I can't find any way, or any resources that will tell me how, to slacken it off. The rest looks fairly straightforward.

Right good news for you then.

If the light isnt coming on with ignition forget about the alternator. Have a look underneath the car infront of the gearbox. There will be a two pin connector. One or both of the wires in this connector will be corroded out (it may not be obvious at first) this is the DMF wire that activates the alternator. Best fix is to cut out the plug and soler the wires together directly.

Cheap as chips.

OK - will do. I need to get the tray off, so it's a bit of a mission.

Speaking of which, is the switch near the ground? The tray was off when I got the car - maybe the switch was getting constantly soaked, leading to the corrosion. I'll be interested to see...

Its not a switch, is a connector in the loom, right at the front of the box so yes would be open to the elements if the tray was missing.

Ross, is this the connector? Sorry, it's slightly out of focus in the photo (you should have seen the Twister-style manoeuvres required to get myself under there!)

It looks incredibly clean inside.

Im trying to work out where that is..lol, got a wider angle shot?

Damn. No. I've put it all back together now!

This is the angle I was shooting from:

I undid two screws from the undertray and pryed-apart a gap big enough to get my hands in. I could see what I was aiming for down through the top of the engine bay - it was a connector on a bracket just in front of the gearbox and just behind the rad fan.

I had to do everything blind, with only my hands in there, but what you see in the picture is the connector (whatever it was), removed from it's little bracket and split apart. One part of the connector is on the right (very out of focus), and the other is on the left (slight out of focus!).

I c now, looks like you in the right place and the connector does look in good order. Usually the conectors are corroded on the female end (bit with the actual clip on it) and they rot out at the end of the connector.

Alternator it is then i guess. To slacken the belt you need to get a spanner onto the tensioner and pull it over and slip the belt off.

Cheers for the advice anyhow - I'm sure someone else on here will find it useful in the future.

So the pulley - do you have to loosen a certain bolt, or are you saying there is somewhere you can place a spanner to pry it back enough to get the belt off?

Its auto adjusting so you just lever is back against its spring.