Thanks for everyone's input.

Going to return the unit then try and source one locally, so I can see it working before purchasing.

Awesome forum and I'll get my profile/intro done asap +++

If you're going to try and get another unit, can I suggest you try and get a A8 BlueTooth phone unit part number 4F1 862 335 instead of 4E0 862 335.

They both share the revised electrical connections you've sorted out but the 4F1 unit [known as a 'BTA'] is a 'better fit' than the more often seen 4E0 unit [known as a 'Handyvorb2'].

The 4F1 unit has an extra connection that lets you use the roof aerial connection that the Motorola unit used. The 4E0 unit makes use of the phone's aerial. The 4F1 potentially gives you better reception with the roof mounted amplified aerial.

Julian

Hi all,

Managed to get another 4e0 unit but am a bit worried about plugging the thing in after the first unit didn't power up.

With the unit off the car can I simply apply 12v to pin 1 and ground to pin 2 and check the red light blinks on the MOST output first?

Also am I correct in thinking that pin 10 and pin 2 should have continuity as they are both off Terminal 31?

Lastly how does the diagnostic wire work? What sort of signal does it send to the Bluetooth unit or does the unit send a signal back. I'm sure when I was checking with a digital voltmeter between diagnostic wire and ground I was getting 12v. Is that correct?

Many thanks for all the help

Ben..

Hi Ben,

When I've tested units on the bench the most optical does blink 3 times then goes off. A good indication that the module works.

As for continuity test, pin 2 to earth yes, not sure about pin 10 as that looks like it goes to the connection in the armrest.

Again, not sure how the diagnostic wire works. I've not looked into it.

+++

Cheers Matt,

Powered up the unit I received today using a bench power supply, Pin 1 connected to 12.5vdc and Pin 2 to 0v return. Switched on the power supply and....... nothing !!! Double checked 12v at the pins.

No blinks from the MOST optical and the unit isn't even pulling any current.

2nd unit off eBay that's been DOA. Currently arranging for it to go back.

I give up for the time being, as I'm getting the right hump with people advertising working units when they obviously aren't and me wasting my time.

Sorry to hear this Ben, what bad luck you've had.

I haven't 'played' myself, but the diagnostic wire is part of the 'Ring Diagnosis' circuit of the MOST connected MMI ECUs. The diagnosis wires from the ECUs are connected in a 'star' together with the Gateway.

When a diagnosis is requested, the Gateway pulses the diagnosis connection to 'wake up' the ECUs which send test signals on the optical loop.

Don't know what the voltage levels are though, sorry ...

Julian

Thanks Julian,

Update - Told the seller I wanted their return address details and that I'd raised a returns request through EBay, to find that he fully refunded me the next hour. They didn't even send return details !!!!