ROG100

Does anyone know or have experiance of the bulb control units and if the various issue numbers are backward compatable?
In particular :-

86 - 928 641 603 05
84 & 85 - 928 641 603 04
83 - 928 641 603 03

Thanks in advance.
Roger

Shane

Roger I put an early '86 (-04) in my '86.5 that had an -05 in it and had no problems.

ROG100

Shane,
Thanks for the quick response - sounds promising.
Roger

PorKen

86 has the additional load of the third brake light.

nosnow

This is an interesting subject. I have an '82 and the PO put in a 3rd brake light and it appears like the OEM unit. If I turn the lights on to "Parking Lights" I get a tail light out, but if I turn the lights on with the brake lights on the warning does not appear. If I turn on the regular lights the warning doesn't appear.

Would this be indicative of the extra load of the 3rd light? I'm wondering if the bulb control unit is from an 86 or the original 82. Would an 86 unit fit in an 82?

Landseer

Roger, I found a (minor) reference to the BCU on the CD's. Doesn't mention later years.

Lifted From pg 31 "Electrical Troubleshooting and Repair 928S":
Bulb Monitoring Unit
The bulb monitoring unit (behtnd CEB) has been revised. The monitoring of electric power for the
tail lights is now accomplished with electronic components and no longer with mechanical reed
switches, The new bulb tester (928.641.603.04) is fully interchangeable with earlier models.


Off topic slightly --- BTW, for anybody with an OB who hasn't stumbled upon it, esp. those us newer to the list, there seems to be a lot of specific diagnostic reference to OB operating systems within the 3 or 4 electrical training documents on these CD's (detailed functionality and connectivity of Alarm, Cruise tempostat; locks; central warning; alternator circuitry including dash resistor, etc.). Helpful.

6mil928

Chris which CD's were you refering to here?

John Struthers

Paul,
Should be a date on your LKU aka BCU.
Ah, the joy of having the cap come loose and SLOWLY figuring where those wires go to.
Pre manual day's, of course.

6mil928

Yep just did this today. Cap was missing completely. Pulled the BCU and bypassed the junk. How sweet no lights on in my cluster

Thanks goes to Landseer for making this all possible

John Struthers

Jason,
My interest is piqued.
How did you bypass?
Did this bypass central warn, oil, water, -later belt warn-as well?
Curious.
FWIW still looking for a Mustang 5.0 or 4.6 modular ignition system/EFI, brain/ harness, with or without dual O2 for ugly FoMoCo /Porsche interchangeability project (OB).
TIA
John S

6mil928

John check this post out.

https://rennlist.com/forums/showthre...ght=BCU+bypass

John Struthers

Jason,
Thanks alot!
John S.

WallyP

The CDs referred to are those prepared and furnished by Jim Morehouse. A huge amount of technical data - every scrap that Jim could buy or borrow - on CDs. Jim's email address is
jim928ATptd.net - change AT to @

John Struthers

Wally P,
When my daughter, Kay, married her knuckle-dragger, Marine and moved to the Carolina's she accidently packed Jim's CD's in with her CD albums and other computer 'stuff'. She's bringing them and some 928 pubs back at Christmas along with my first grandchild.

6mil928

your very welcome john. I heard that the info is excellent. I'll get them in the near future.