Blower not working

[C4_owner_pj]

Hi,

I have been reading a lot of threads having the same problem. Blower not working. But I cant seem to find out if there can be a relay thats defect or not in my model. It seems to me my blower works (tested on battery) and resistor pack seem to work as well. I tried measuring voltage and it seems to be the blower does not get any power. What components can be causing the blower not to get power?

Its a C4 Grand Picasso 2010, VIN VF7**************[VIN obfuscated, can be read by forum staff].

The blower when it started to fail worked occationally. Sometimes worked, next time didn’t work. So it just got worse over time and now its totally dead.

[ozvtr]

Sorry but i don't have a circuit diagram for your car but the circuits generally follow the same pattern.

Typically power comes from the battery through the maxi fuses (under the BSM fusebox in the engine bay) to the BSM, through "blower fan" fuse, switched by a relay in the BSM. Then to the positive of the fan motor, through the fan, to the selector switch, to the resistor pack then to ground.
Typical failure modes are:
Burnt out resistor. Can be tested with a multimeter on ohms.
Burnt out contacts in the selector switch. Can be tested with multi meter but better to pull it apart and look. Test for voltage at resistor.
Burnt out contacts on fan motor or burnt out motor. You have apparently tested the motor?
Burnt out contacts on connectors between components. Remove all the associated connectors and inspect the contacts for carbonization or melted plastic.
Burnt out contact of relay in BSM. Test for volts at the positive terminal of the fan with the fan running, or set to 'on' if it's not running.
Blown or bad "blower fan" fuse. Test for voltage on both sides of fuse.
Blown or bad maxi fuse. This will power other circuits so if nothing else has stopped working, unlikely to be that.

[C4_owner_pj]

Thanks for the reply. I have used a multimeter to test the voltage when fan is on, and I got 0 voltage. The resistor seems to be good when testing resistance (ohms). I do want to check if I have chekced the right fuse and see if I can find a relay to test. My problem there is that I am unsure which fuse, but I have checked the ones I found in the cars manual, and some more (Have not measured voltage on fuse). I really want to find and test the relay, but I do not know where tis is. When you say in BSM I cant seem to find many relays. There is one green one tucked in front of the BSM, but I have no idea what that one is for. I am not at home now, but can take som picture of BSM and post when I am back home.

[ozvtr]

The relay is probably inside the BSM. Again, not familiar with the Picasso but the PSA BSM's seem to follow the same pattern (relays inside the BSM).
The blower fan fuse is typically 40 amps and is orange. Most of the other circuits are broken up into sub-circuits and draw less current. That circuit is usually the biggest (value) fuse in the BSM.
The fuse should be located in the circuit before the relay. Meaning, if you have voltage at the fuse but not at the fan motor, then the relay is probably not working.

[C4_owner_pj]

Hi,

I am starting to think I have to take the car to a garage I am not sure what you mean by inside the BSM, but I have attached two images - do I have to take the BSM out? I also can not find 1 fuse thats for the blower in the cars manual. You can see a green relay in the picture, but I have no idea what it is connected to. As you probably get by now, I am not a car mechanic

[ozvtr]

Yes, inside the BSM.
The BSM typically contains a large Printed Circuit Board with the electrical connectors, fuse holders, electronics and relays (a lot of relays) soldered directly onto the board. Most other manufacturers of this type of unit have plug in relays to make replacement easy, but not PSA, oh no!
As I said typically the blower relay is in the BSM. Unfortunately I do not have access to a circuit diagram and I can not confirm that. However it should be easy enough to follow the wiring from the blower motor to the BSM to confirm it.
The question is then; do you have the skill to track down and remove, then replace the relay? If not you you would be looking at the cost of "another" BSM. Either you replace it or a mechanic replaces it. The BSMs don't require coding or anything like that they just "drop in".

[C4_owner_pj]

Thanks. That was what I feared. I might have the skill, but not sure if I have the time. Think I might ask a friend here...