Peugeot 308 T7 - Headlights flash and wipers move during CAN wake-up after BSM R20 replacement

[pedrocaldas]

Hi everyone,

I'm looking for some technical insight from people familiar with PSA electrical systems.

I have a **Peugeot 308 T7 THP** (Brazilian market, manufactured in Argentina).

My original **Delphi BSM R05 (ending in 8480)** failed after the A/C fuse overheated and melted the fuse holder. It also left the low beam relay permanently ON.

I replaced it with a **new aftermarket BSM R20 (ending in 9480)**, sold as a direct replacement.

Since the replacement, the car works perfectly:

* Engine runs perfectly.
* Everything works flawlessly (incredible!)
* No CAN communication faults.
* No fault codes.
* All electrical functions work normally.

However, after the car goes to sleep (economy mode), every wake-up causes the following:

* The low beams flash once.
* The windshield wipers move a few centimeters.

If I repeat the wake-up several times (locking/unlocking the car without starting the engine), the wipers eventually perform a full wipe because each wake-up moves them a little farther.

This behavior **never happened with the original R05**. It started immediately after installing the aftermarket R20.

I'm trying to determine whether this is:

* A known difference between the R05 and R20 hardware revisions.
* An aftermarket BSM timing/initialization issue.
* A BSI software compatibility issue (maybe software update via Diagbox?).
* Or something related to the wiper park circuit.

Has anyone seen this before?

Any information, wiring diagrams, oscilloscope captures, PSA service bulletins, or personal experience would be greatly appreciated.

Thank you!

[mickthemaverick]

I'm not sure about this but I think you may be able to get the BSI to recognise the wiper motors by simply telling it you have replaced them and it may then recalibrate them and possibly cure the wiper issue. The single flash of the lights I would view as an 'I'm awake' message!!

[pedrocaldas]

i didn't replace the wiper motors, only the bsm. The issue is that during time, the dry sweep will scratch the windshield, and i want to avoid that.

[PaulC5]

Check the battery voltage in case it needs charging. In the end you might have to fit the correct part.