My boot has stopped opening on the key fob and the button on the boot. I've bought a new boot motor unit which arrived today so I thought I'd give it ago.

 

I checked to see if the new motor worked by passing 9v across the terminals (less than 12v to usually gets) and it triggered (all be it slowly). I unplugged the connector from the old motor and plugged it into the new one and it's still not working.

 

I checked the pins to see if there is any voltage across them between the live and the earth and I'm getting nothing which explains why the boot motor is not triggering. Checked the fuse box and fuse 31 had gone. Replaced it, but still nothing... There are ~12v across the fuse terminals though.

 

Would anyone be able to help me interpret the wiring diagram so I can continue hunting the issue down?

 

This is a link to what I believe to be the right wiring diagram.

 

I think that V53 is the motor, E234 is the boot release switch on the tailgate and, SB31 is shown in the fuse box. There is a relay between connectors T6o/5 and T6o/6 which I assume is what closes to send the power through the boot motor.

 

Few questions:

1. Is the gray box at the top the electronic control unit, and is this the same as the engine control unit?
2. if the 'electronic control unit' is not the same as the engine control unit, where do I find the electronic control unit?
3. Am I right in saying that T6o/5 and T6o/6 are two connections on a 6 pin connector with the designation 'o'? If that is correct, how do I locate these connections on the ECU?
4. What does the XP1 mean shown on the ECU just about T6o/5 and T6o/6?
5. Can I get access to that relay, or is it within the ECU itself? It might be what has broken...

Many, many thanks in advance for any help on this.

Edited 23 June, 20188 yr by mr_bristol

Grey box at the top is the On-board supply control unit which lives above the accelerator pedal.

T6o is indeed a 6 way connector, plugs in where the XP1 label is on the control unit.

The relay is soldered to the circuit board within the controller. 

 

I'll try to add some pictures soon.

Blown fuse plus no volts where there should be may suggest a broken wire which shorted to chassis?

8 minutes ago, Wino said:

Grey box at the top is the On-board supply control unit which lives above the accelerator pedal.

T6o is indeed a 6 way connector, plugs in where the XP1 label is on the control unit.

The relay is soldered to the circuit board within the controller. 

 

I'll try to add some pictures soon.

Thanks for your quick reply on this. "[A]bove the accelerator pedal" that sounds nice and easy to get to.....

 

If I stick my volt meter into T6o/5 and click the button on the fob, I assume I should see 12v coming out of this. If so, then the wire is broken somewhere between the box and the motor, and if not, there's no hope as the problem lives within the box. Is that correct?

 

"Blown fuse plus no volts where there should be may suggest a broken wire which shorted to chassis?"

 

Exactly my thoughts, however, I replaced the fuse and clicked the fob relentlessly and the fuse hasn't blown. Though, it may be that the wire is fraid and touching the chassis round corners or something.

 

Out of interest, how did you know that was the supply control unit, and not the ECU from the wiring diagram?

Edited 23 June, 20188 yr by mr_bristol

It's not too bad to get to, the lower dash cover has to come off, see the guide for evaporator temp sensor replacement for one 'how to' on its removal.

Spot on with your voltmeter plans.

In early versions of the current flow diagrams, that grey box is labelled J519, and the key explains that this is the onboard supply control unit. In later diagrams it just seems to be assumed. Engine ECU doesn't deal with much that isn't directly engine related. When it is shown, it's usually lower on the page and explicitly labelled

Edited 23 June, 20188 yr by Wino

Here's the control unit in position, but I don't think the connector in question is visible in this shot: