Curious to know

[egremont]

Excuse me for asking, but I am curious as to why a Battery Back Up Alarm needs to be installed in our care when upgrading headlamps to xenons.

If these alarms are that better, why weren't they incorporated in the first place.
Regards,
egremont.

[klarzy]

Originally Posted by egremont

Excuse me for asking, but I am curious as to why a Battery Back Up Alarm needs to be installed in our care when upgrading headlamps to xenons.

If these alarms are that better, why weren't they incorporated in the first place.
Regards,
egremont.

The BBUS (Battery back up sounder) is partly used as a controller for the headlamp cleaning system on OEM HID installations, the headlight washers wont work without it and a T4 session or some DIY relay wiring.

Note: headlamp washers are not required if you are just upgrading the headlamp units to HID OEM type.
Its a case in the MOT that they have to work if fitted, not that they are there in the first place.

also do not confuse Xenon (MG/R's name got HID headlights) units and Xenon gas filament bulbs which fit into standard halogen units...

[kelvo]

Originally Posted by klarzy

Note: headlamp washers are not required if you are just upgrading the headlamp units to HID OEM type.
Its a case in the MOT that they have to work if fitted, not that they are there in the first place.

I thought that with Xenon/HID you have to have headlamp washers and self-levelling, which is where a lot of these DIY installations will fail the MOT?

[suzublu]

Originally Posted by kelvo

I thought that with Xenon/HID you have to have headlamp washers and self-levelling, which is where a lot of these DIY installations will fail the MOT?

I've had xenons fitted for 8 years without anything else & had no problems

[klarzy]

Originally Posted by kelvo

I thought that with Xenon/HID you have to have headlamp washers and self-levelling, which is where a lot of these DIY installations will fail the MOT?

the wording of the MOT states:

check headlight wash and self levelling systems

if they are not there, they can not check them...
if they are fitted, then they must work.

[klarzy]

here is the draft new MOT.
for BOTH self level and wash it is a check if present...



Self levelling MAY BE FITTED
you must check VEHICLES EQUIPPED WITH

in neither case does it state that if not equipped it is a fail.

[Bolin]

BBUS is required because the Powerwash uses the same relay for power as the ordinary alarm horn - the BBUS doesn't need a relay and MGR didn't add an extra slot for another relay so one had to do either the alarm horn OR Powerwash.

So when they fitted Pwerwash at the factory they used the alarm horn relay and fitted a BBUS as it didn't need one.