Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Immobiliser & other warning lamps

A brief update! The replacement PCB didn't cure the fault; with the connectors on the reservoir cap removed, during a further test drive, the light still flashed! So attention moved to the handbrake switch connections & the wiring loom to it. 'wrapping' the wires in a plastic sleeve where they pass over the gearbox & using cable ties to secure as well as checking for possible chaffing of the wires from the bulkhead resulted in no flashing during a further test run. However, after about 15 miles of driving back home there was one brief flash of the light. A further 15-20 miles no further problem. Will monitor closely, & when the opportunity of getting the car on a ramp again arises, have a further inspection.
Thank you for all the suggestions & advice.

Peter there are three triggers on the loom that can bring on that light. The left and right brake fluid level sensor cap connections (one redundant dependant on l/h or r/h drive car) plus handbrake connector. All signal wires are black/white and are paralled to a single wire of same colour running to the 9 way Tyco connector (only eight pins used) feeding driver LED warning strip. A short to ground at any point on these wires will trigger the warning. I could be you have found such but a little concerned fault re-appeared even though just once!

You haven't mentioned if you checked the redundant wires to l/h drive position of brake master cylinder. These should be individually insulated and cable tied out of harms way.

Not sure what "PCB" you replaced but the GDI model's (2014 on) employed a sealed BCU, was it just the warning light strip interfacing with the above mentioned connector?

FYI Richard the bcu is not sealed there's just nothing you can do with it. With a lot of trial and error one might manage to find out what relay did what function. Everything is soldered to the board.

Many thanks John. Perhaps I should have said protected rather than sealed to differentiate between BCU and the earlier various and infamous PCB's that did a similar job.

Someone on TM did identify the four relays in the Plus 4 BCU but cannot remember who or find where.

OK, perhaps I took it too literally?

Yes now you mention it, you are correct someone did identify the relays, can't remember his handle, the avatar was a single seat race car?? Oh my memory!! or lack of.

Is this what you are referring to ?
Board

Sorry no, it's in regard to this image I believe of the BCU on a GDI Plus 4. 3.7 Roadster BCU is similar but has some differences.

Looks remarkably similar Richard, this is inside a 3.7 BCU (early production model)



Did the OP manage to work out the function of each relay ?, as the one above has occasional indicator faults

Thank you for your continued advice Richard & everyone.
The PCB I referred to is the small one behind the warning lamps, between the fuel & temp gauges. It would appear this has been redesigned although completely interchangeable with the original.
'You haven't mentioned if you checked the redundant wires to l/h drive position of brake master cylinder. These should be individually insulated and cable tied out of harms way.'
We'll have to check this when the car is up on the ramp.
Have to say I am completely out of my depth with this sort of thing!
A short drive yesterday, (after having the wheels off to give a good clean) & once again no sign of the lamp flickering!

Further brief update; a number of short runs & no more flickering, off to Mogfest at the weekend, should be a good test!