[928uk] bulb monitor ecu

[Paul R Smith]

Yes, I have towed one 928 on a trailer behind another 928 (not 
advisable, and probably not legal weight wise), but mostly just my 
un-braked motorcycle trailer that has also carried lots of other 
(inanimate) things too. I'm sure it's surprised a lot of people.

Smiffy

On 03/06/2024 16:09, Richard Armstrong via 928uk wrote:
> First rule of holes Paul.......!!😁😁
> So Smiffy has sheep. Baaaa
> Richard
>
> On 03/06/2024 15:31, Paul Lacey via 928uk wrote:
>> Oh dear, it was a joke - read Smiffy's answer.
>> What's he doing fitting towbars to his 928's ? Perhaps for his 
>> trailer taking piggies to market ?
>>
>> P.S. that's also a joke I'm not suggesting Smiffy has piggies, 
>> obviously it's for his sheep
>>
>> PL
>>
>> -----Original Message-----
>> From:jonathanrackowe at gmail.com [mailto:jonathanrackowe at gmail.com]
>> Sent: 03 June 2024 15:24
>> To: 'Paul Lacey'
>> Cc: '928 List'
>> Subject: RE: [928uk] bulb monitor ecu
>>
>> I have no idea what you’re on PL !
>>
>> Phil Rick started this thread with a query about the 92864160309 or 
>> 92864160311 bulb monitor units for a 90 model year 928.
>>
>> Earlier bulb monitor units and towbars have nothing to do with the 
>> operation of the 87 onwards S4/SE/CS/GT/GTS bulb monitor units.
>>
>> Best regards,
>> Jonathan
>>
>> 1991 928 GT Amethyst Metallic
>>
>>
>>
>>
>> -----Original Message-----
>> From: Paul Lacey<t595 at btinternet.com>  Sent: 03 June 2024 15:17
>> To:jonathan at rackowe.net;smiffypr at gmail.com
>> Cc: '928 List'<928uk at lists.928.org.uk>
>> Subject: RE: [928uk] bulb monitor ecu
>>
>> No Jonathan,
>> It's all about towbars on 928s - WTF
>> :-)
>>
>> Paul L
>>
>> -----Original Message-----
>> From: 928uk [mailto:928uk-bounces at lists.928.org.uk] On Behalf Of 
>> jonathanrackowe--- via 928uk
>> Sent: 03 June 2024 14:52
>> To:smiffypr at gmail.com;928uk at lists.928.org.uk
>> Cc:jonathanrackowe at gmail.com
>> Subject: Re: [928uk] bulb monitor ecu
>>
>> But this discussion is about the 87 onwards S4/SE/CS/GT/GTS bulb 
>> monitor units and has been since the start!
>>
>> Best regards,
>> Jonathan
>>
>> 1991 928 GT Amethyst Metallic
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: 928uk<928uk-bounces at lists.928.org.uk>  On Behalf Of Paul R 
>> Smith via 928uk
>> Sent: 03 June 2024 14:01
>> To:928uk at lists.928.org.uk
>> Subject: Re: [928uk] bulb monitor ecu
>>
>> Jonathan, you looked at an '87 onwards version, the earlier ones are
>> different. The tail lamp warning does work on balance, and the brake
>> lamp circuit needs a minimum current (not a window).  I have had my
>> towbar fitted to my '80 and '84, and I would get a warning if only one
>> trailer tail light was working, and I didn't get any warnings caused by
>> the extra load.
>>
>> Smiffy
>>
>>
>>
>> On 03/06/2024 13:07, jonathanrackowe--- via 928uk wrote:
>>> George, you are repeating the old myth that the bulb monitor 
>>> compares the load one side with the other. As I have said before at 
>>> least twice on this list, it simply does not work that way.
>>>
>>> The bulb monitor separately monitors the current through each brake 
>>> light bulb and through each set of tail light bulbs. The unit 
>>> contains four 'window' comparators to check that each of the four 
>>> monitored currents is within an absolute 'window' - i.e. not too 
>>> high and not too low. That way it can detect bulb failure (open 
>>> circuit or short circuit) or an incorrect bulb (too little or too 
>>> much current flow).
>>>
>>> You are correct that the 3rd brake light is connected in parallel 
>>> with only one of the brake light bulbs (left side I believe) and so 
>>> the bulb monitor is modified to have a different 'window' of 
>>> acceptable current for that specific brake light.
>>>
>>> There is nothing in the wiring diagrams to indicate that the Porsche 
>>> mobile phone kit was connected in any way to the bulb monitor. I 
>>> suspect I was repeating a rennlist myth myself there!
>>>
>>> Best regards,
>>> Jonathan
>>>
>>> 1991 928 GT Amethyst Metallic
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: 928uk<928uk-bounces at lists.928.org.uk>   On Behalf Of George 
>>> Layton via 928uk
>>> Sent: 03 June 2024 11:46
>>> To:928uk at lists.928.org.uk
>>> Subject: Re: [928uk] bulb monitor ecu
>>>
>>>    From what I recall when I fitted a 3rd brake light to my GTS (it was
>>> many years ago and my brain is now old) the light takes its power from
>>> the circuit on 1 side at the rear. I understood that the bulb 
>>> monitoring
>>> unit had to be changed to allow for the now "unbalanced" load comparing
>>> one side to the other.
>>>
>>> Perhaps the mobile phone kit drew power from the circuit on one side of
>>> a pair being monitored by the unit and so the unit had to be updated??
>>>
>>> George.
>>>
>>>
>>> On 03/06/2024 11:18, jonathanrackowe--- via 928uk wrote:
>>>> Yeah, I struggled to see the connection between the bulb monitor 
>>>> unit and the 90's mobile phone kit… but then who would doubt the 
>>>> infallibility of rennlist info!! 😃 (joking comment for those 
>>>> reading this in plain text without emoticons)
>>>>
>>>>
>>>> Maybe 928 641 603 10 flashes the brake lights if you're on the 
>>>> phone! 😉  (another joking comment for those reading this in plain 
>>>> text)
>>>>
>>>> Best regards,
>>>> Jonathan
>>>>
>>>> 1991 928 GT Amethyst Metallic
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: 928uk<928uk-bounces at lists.928.org.uk>    On Behalf Of Paul R 
>>>> Smith via 928uk
>>>> Sent: 02 June 2024 16:12
>>>> To:928uk at lists.928.org.uk
>>>> Subject: Re: [928uk] bulb monitor ecu
>>>>
>>>>
>>>> I searched on this 928 641 603 10 in my PET, and it does find it, 
>>>> but it also shows
>>>>
>>>> Market as USA.
>>>>
>>>> It quotes this number for up to 1990 with or without option 612 (prep
>>>>
>>>> for phone) and 1991 onwards with no mention of option 612.
>>>>
>>>>
>>>> I don't know what the link is with the phone kit, but it looks like it
>>>>
>>>> is a red herring. 10 appears to be for all US versions 1987 onwards.
>>>>
>>>>
>>>> Smiffy
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From:jonathan at rackowe.net    Sent: 02 June 2024 11:53
>>>> To: phil rick<philrickse at gmail.com>
>>>> Cc:928uk at lists.928.org.uk
>>>> Subject: RE: [928uk] bulb monitor ecu
>>>>
>>>>
>>>> If anyone ever comes across 928 641 603 10, that was a version of 
>>>> the bulb monitor with modification for in-car telephone use.
>>>>
>>>>
>>>> 928 641 603 09 Bulb control unit - rear lights (on left of 
>>>> passenger gloves shelf in UK)
>>>>
>>>> 928 641 603 10  Bulb control unit - rear lights with modification 
>>>> for in-car telephone use
>>>>
>>>> 928 641 603 11 Bulb control unit - rear lights with additional high 
>>>> rear brake light
>>>>
>>>>
>>>> Best regards,
>>>>
>>>> Jonathan
>>>>
>>>>
>>>> 1991 928 GT Amethyst Metallic
>>>>
>>>>
>>>>
>>
>>
>>
>