Body Control Unit question

Raistlin · 7th November 2007, 19:04

A question for the gurus please:-

It appears that the BCU might be responsible for enabling headlamp powerwash.

My BCU allows rain sensing wipers to work but SEEMS not to allow powerwash.

Les, from SMC has a car fitted with powerwash but probably not rain sensing wipers.

64 thousand dollar question:-

Will the BCU from the car SMC has also work with rain sensing wipers?

Help greatly appreciated please.

JohnDotCom · 7th November 2007, 20:16

There is several variations available for the BCU's have you checked your model on EPC Paul?

SMC Trading · 7th November 2007, 20:36

Body Control Unit

So thats what BCU stands for

, felt silly asking....

Greeners · 7th November 2007, 20:52

First check....get the part number from Les and check on EPC what it covers

it'll be either 2 windows and or 4 windows and or rain sensor.

Then compare it to what you've got.

Raistlin · 7th November 2007, 20:58

Quote:

Originally Posted by Greeners

First check....get the part number from Les and check on EPC what it covers

it'll be either 2 windows and or 4 windows and or rain sensor.

Then compare it to what you've got.

Well

Mine HAS to be 4 windows and rain sensing wipers David as they all work on my car.

If that is the highest level of BCU then maybe it's not the cause of my powerwash problem?

JohnDotCom · 7th November 2007, 21:07

The four window model with wiper sensing is the one I have bought (new) for the power wash then realised it is the same one I already have fitted and wiring etc is all ready fitted behind bumper etc.

Raistlin · 7th November 2007, 21:16

Quote:

Originally Posted by JohnDotCom

The four window model with wiper sensing is the one I have bought (new) for the power wash then realised it is the same one I already have fitted and wiring etc is all ready fitted behind bumper etc.

In that case John, our theory about powerwash being controlled by the BCU goes up the chute

stocktake · 7th November 2007, 21:49

Paul,
Don't know if you have read this on RAVE.

Powerwash:

A permanent 12V supply from the battery, via fusible link 3 in the engine comartment fusebox is connected to the powerwash relay contacts and coil in passenger compartment fusebox. For the powerwash to operate the BCU must receive a KBus message from the LSM that the headlights are on.

When the programmed wash wipe is operated an earth path is completed from the BCU through the switch. This is interpreted by the BCU as a signal that programmed wash/wipe has been requested. If the BCU receives the lights on K bus message from the LSM, the BCU provides an earth for the coil of the powerwash relay which energises and closes the relay contacts. The feed from fusible link 3 passes through the relay contacts and fuse 30 in the passenger compartment fusebox and is connected to the powerwash pump which operates. The BCU energises the coil for 750 milliseconds allowing the pump to operate to vclean the headlights.

A counter in the BCU starts and prevents further powerwash operation for the next four programmed wash/wipe switch operations. On the fifth operation of the switch the BCU permits powerwash operation and resets the counter. The counter is always reset when the ign is switched off.

Hope that is of some use to you. ( took long enough to type..

)

Raistlin · 7th November 2007, 22:05

Thanks Dave

In that case - everything SHOULD work.

What, I wonder is 'programmed' wash wipe?

stocktake · 7th November 2007, 22:23

Quote:

Originally Posted by Raistlin

Thanks Dave

In that case - everything SHOULD work.

What, I wonder is 'programmed' wash wipe?

pulling up on your stalk!!!!!!!!!

(can I say that on Here?)

7th November 2007, 19:04	#1
Raistlin Banned 75 CDT Connoisseur SE Auto Join Date: Nov 2006 Location: Wolverhampton Posts: 8,450 Thanks: 0 Thanked 3 Times in 3 Posts	Body Control Unit question A question for the gurus please:- It appears that the BCU might be responsible for enabling headlamp powerwash. My BCU allows rain sensing wipers to work but SEEMS not to allow powerwash. Les, from SMC has a car fitted with powerwash but probably not rain sensing wipers. 64 thousand dollar question:- Will the BCU from the car SMC has also work with rain sensing wipers? Help greatly appreciated please.

7th November 2007, 20:52	#4
Greeners Moderator MG-ZTT Join Date: Mar 2007 Location: Ware, Herts Posts: 19,798 Thanks: 161 Thanked 1,249 Times in 1,036 Posts	First check....get the part number from Les and check on EPC what it covers it'll be either 2 windows and or 4 windows and or rain sensor. Then compare it to what you've got. __________________ *David* Impecunity is the mother of ingenuity Useful how to's for common problems Car Of The Month Jan 2014 [SatNav Power Down] [Coolant Level] [SatNav Repair] [Diesel Non Starting] [Paint Codes] [Rear Light Seals] [Reversing Light Switch] [Bleeding Brakes][Sunroof Drain] [Early ZT's][Instrument Pack Diagnostics][ATC Diagnostics]

7th November 2007, 21:49	#8
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,591 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Paul, Don't know if you have read this on RAVE. Powerwash: A permanent 12V supply from the battery, via fusible link 3 in the engine comartment fusebox is connected to the powerwash relay contacts and coil in passenger compartment fusebox. For the powerwash to operate the BCU must receive a KBus message from the LSM that the headlights are on. When the programmed wash wipe is operated an earth path is completed from the BCU through the switch. This is interpreted by the BCU as a signal that programmed wash/wipe has been requested. If the BCU receives the lights on K bus message from the LSM, the BCU provides an earth for the coil of the powerwash relay which energises and closes the relay contacts. The feed from fusible link 3 passes through the relay contacts and fuse 30 in the passenger compartment fusebox and is connected to the powerwash pump which operates. The BCU energises the coil for 750 milliseconds allowing the pump to operate to vclean the headlights. A counter in the BCU starts and prevents further powerwash operation for the next four programmed wash/wipe switch operations. On the fifth operation of the switch the BCU permits powerwash operation and resets the counter. The counter is always reset when the ign is switched off. Hope that is of some use to you. ( took long enough to type..) __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident Last edited by stocktake; 7th November 2007 at 22:21..

7th November 2007, 20:16	#2
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	There is several variations available for the BCU's have you checked your model on EPC Paul?

7th November 2007, 20:36	#3
SMC Trading I really should get out more....... Rover 75 Join Date: Nov 2006 Location: Nr Harlow Posts: 2,872 Thanks: 1 Thanked 6 Times in 5 Posts	*Body Control Unit* So thats what BCU stands for , felt silly asking....

7th November 2007, 21:07	#6
JohnDotCom * Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver Join Date: Nov 2006 Location: Abergele Posts: 28,735 Thanks: 0 Thanked 6 Times in 5 Posts	The four window model with wiper sensing is the one I have bought (new) for the power wash then realised it is the same one I already have fitted and wiring etc is all ready fitted behind bumper etc.

7th November 2007, 22:05	#9
Raistlin Banned 75 CDT Connoisseur SE Auto Join Date: Nov 2006 Location: Wolverhampton Posts: 8,450 Thanks: 0 Thanked 3 Times in 3 Posts	Thanks Dave In that case - everything SHOULD work. What, I wonder is 'programmed' wash wipe?