C4GP fan blower problems - please help

[Elts]

Hello folks,

The wife’s C4GP (2016) has a problem where the screen demist blower doesn’t blow. This issue started off as intermittent, but is now full time. I’ve tried swapping out the relays behind the glovebox, and a small 3 relay pack located behind the blower chambers, but the fault is still apparent.

Can someone provide the schematics / wiring diagrams please so I can try and properly fault find?

The aircon has recently been fixed bu our local garage. The Anniss’s predates the aircon fix (this was due to a leaking pipe).

Happy to take any advice / pointers as I want it fixed before the cooler weather sets in again.
VIN VF7**************[VIN obfuscated, can be read by forum staff]

Based in Aberdeenshire, Scotland.

[PaulC5]

When the blower on our Cactus stopped working it needed a new blower resistor pack.

[Elts]

I have read about the resistor pack failing, but can’t seem to physically locate it.

[GiveMeABreak]

See my post here: viewtopic.php?p=614598#p614598 Item (3) on the diagram, and below (2) in location:

[Elts]

Time for an update.

I replaced the resistor pack today, and the fault has changed, so I assume multiple faults. Brilliant.

Current status: with the car ignition on (engine off) I have full manual control of the blowers, until I switch the delist on when it runs for a split second then cuts off. When I deselect the screen blower it starts blowing again and I get control back of the fan.

If I start the engine the blowers do not operate.

Please, if anyone has access to the schematics or advice, let me know!

[GiveMeABreak]

Here's a schematic:



With the exception of the wiring codes, most of the component codes are indexed here:

PSA Electrical Diagrams - Wiring & Symbols Codes Index

[Elts]

Thanks Marc. I can figure out the interconnect diagram above, and some of the components (bb00 battery, psf1 is under bonnet fuse box, bsi1 is the bsi behind glove box), but how do I identify and then find the other areas?
I understand that all of the 80’s are linked to the heating/venting/aircon system, but that doesn’t really help.

I need to find where the power to the fans when the engine is running is different from ignition power only.

[GiveMeABreak]

It's a digital system, and internal details off the units are not available, but I have the Pin Info:

The air blower control module control signal is a digital signal of the opening cyclic ratio type.
The value of the cyclic ratio of the control signal defines the power demanded by the driver or front passenger.

"a": 2 way connector

Channel No.	Allocation of channels of connector
3	Earth
4	Battery +

"b": 2 way connector

Channel No.	Allocation of channels of connector
1	Air blower value
2	Diagnosis

"c": 2 way connector

Channel No.	Allocation of channels of connector
5	Engine control -
6	Engine control +

The only other thing I can think of is the actual Air Conditioning Control ECU itself, which is set back further against the evaporator unit as you can see at (3):

This unit controls everything from the stepper motors to the air distribution etc. and of course commands the Control module for the blower motor.

"a" 40-way blue connector

1	A2 phase signal : Mixing stepper motor (right side)
2	B2 phase signal : Mixing stepper motor (right side)
3	A1 phase signal : Air intake stepper motor
4	B1 phase signal : Air intake stepper motor
5	A2 phase signal : Air intake stepper motor
6	B2 phase signal : Air intake stepper motor
7	Sunshine sensor signal
8	Sunshine sensor earth
9	Signal from the evaporator temperature sensor
10	Earth of the evaporator temperature sensor
11	B1 phase signal : Mixing stepper motor (right side)
12	A1 phase signal : Mixing stepper motor (right side)
13	Channel not connected
14	Channel not connected
15	Channel not connected
16	Channel not connected
17	Channel not connected
18	Channel not connected
19	Channel not connected
20	Air blower value
21	A2 phase signal : Distribution stepper motor
22	B2 phase signal : Distribution stepper motor
23	Air blower diagnostic link
24	Channel not connected
25	Channel not connected
26	Channel not connected
27	Supply of the distribution stepper motor
28	Supply of the air intake stepper motor
29	Supply of the mixer stepper motor (right side)
30	Supply of the mixer stepper motor (left side)
31	B1 phase signal : Distribution stepper motor
32	A1 phase signal : Distribution stepper motor
33	B2 phase signal : Mixing stepper motor (left side)
34	A2 phase signal : Mixing stepper motor (left side)
35	B1 phase signal : Mixing stepper motor (left side)
36	A1 phase signal : Mixing stepper motor (left side)
37	Channel not connected
38	Channel not connected
39	Channel not connected
40	LIN

"b" 6-way black connector

Channel number	Allocation of channels of connector
1	Earth
2	Channel not connected
3	ECU 12 V +ve supply
4	Comfort CAN High
5	Comfort CAN Low
6	LIN

[Elts]

Thanks Marc,

I’ll take a look at the power coming in to the 2 way connector ‘c’, as that sounds like it might be the power for fans at engine running stage.

[Elts]

So in a bizarre turn of events, after measuring the voltages on the resistor connectors (12v when ignition only, 14+ with engine running) the fault has again changed slightly. Still no blower setting available (but can turn the fan up and down) in ignition only, but occasionally on engine start the fan will work for a few seconds then all switch off. The rear fans work unless the screen blower is selected, then everything cuts off.

[Elts]

Update - I have now changed out the item 3 (is this the unit marked 8080?) for a 'preloved' unit, and still have the same issues.

In ignition (engine off) I can control the fans, apart from the blower setting which turns all fans off. With he engine running I. can usually (but not always) control the fans, but again when blower selected everything shuts off.

From the diagram above I suspect that something in the PSF1, BSI or another unit has failed and either isn't supplying a signal path (or earth return) for the command from the blower/demister selector.

There doesn't appear to be anyone with a newer diagnostics tool near me (NE Scotland), so it seems like my next logical step is find a trusted autoelectrical garage...

unless anyone else has any input / advice?

I can't find relays 6 & 16 (PSF1) - can anyone point me in their direction?

[GiveMeABreak]

Engine Fuse box relays are internal to the fuse box - they are not intended to be user serviceable components.