C4 Picasso heater blower

[niallmoran]

Evening chaps

Been trying to sort out the issue with our C4GP heater blower that suddenly stopped working a couple of weeks ago. Initially i thought it was the resistor pack as having had a few scenics in the past they were a common problem but it turns out it's not as simple as that.

So far, i've confirmed that the motor runs fine when powered but also that there is no power coming to the resistor pack (the control panel is still powered). Providing direct power to the resistor pack gets the system working fine with the buttons controlling the fan as normal. Having checked the fuses under the bonnet i can't find any issues but i'm a bit vague on what fuses do what as the manual isn't the best

So, what are the likely culprits? I've seen on other posts that the fuse box/bsi might be a weak point and that bridging the two white wires leading into fuse box bypasses the relay but that didn't work

Cheers
Niall

[GiveMeABreak]

Niall,pop your VIN up here so I can check out the fuses and diagrams for your specific vehicle.

[niallmoran]

Thanks Marc - that would be great

It's VF7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

Ok, so there are several possibilities:

The Driver's Heater Control Panel is shown at 8021. Pin 4 goes to the Passenger Compartment Fuse Box (BH12), and is controlled by Fuse 37.
Fuse F14 in the BSI Fuse Box in the cabin is the Control panel - Air Conditioning ECU.
8023: Is the Passenger´s Aircon Control Panel
BF03A: Is the maxi-fuse output service battery positive (controlled by Maxi Fuse 7) in the Engine Fuse Box (PSF1).
8048: Is the Blower Relay
Wire 8020 is the Air Conditioning Motor Control that goes from the Blower Control Module to the Blower Relay (8048)
8045: Is the Blower Control Module (if separate)
Fuse F11 in the Engine Compartment Fuse Box is for the rear Air Conditioning Blower Control

So possibly the relay (8048) is the culprit.

As for the parts - you only have the Heater Control Module item 3 on your vehicle (not item 11) which I think you've said you have checked as being fine. When these go, it is usually blowing full or nothing.

[niallmoran]

Thanks Marc - that should hopefully help me track down the fault. In terms of the relay, where would i find 8048?

[GiveMeABreak]

I'm afraid I can't help you with the relay location - it isn't shown specifically - but may be inside the relay box (Part 8) on the diagram below, which is usually located near the engine fuse box.

This should be what you are looking for - once you find it - use the wiring diagram to check the wires. There should be some wiring codes on the wire sleeve, so 8020 is shown on Pin 5. It is shown as having only 4 wires in the 5 pin relay. It could be there.

[niallmoran]

fantastic - i'll try and have a root around tonight and see what i can find....fingers crossed it's just a relay as that would be nice and simple. I was tempted to just bodge it and grab a 12v feed from somewhere else and while that would probably work in the short term it would probably cause other issues

[niallmoran]

ok, i found the relay (i think) - it was tucked into the space in front of the main fusebox (didn't look like the pic above - there was only) and it has signs of heat damage so hopefully a new one will do the trick! The original is a G.CARTIER RELAY 12V 35A 03531 but i was wondering if this one from halfords will do the job?

https://www.halfords.com/workshop-tools ... -40a-5-pin

Nice and easy if i can just pick up from halfords and we'll be able to get some air back into the old bus

[Hell Razor5543]

I would spray some proper contact cleaner into the socket first, and then plug/unplug the relay a few times, to clean any tarnish off the contacts.

[niallmoran]

good idea james - i think i've got a can of contact cleaner in the shed

[GiveMeABreak]

The old one is knackered - that much is obvious - no amount of cleaning is going to resurrect that - you need a new relay!

As for the Halfords one - no that is the wrong one and is rated too high (40 A).

You need part number: 6547TX

These can be bought new from a Peugeot or Citroen dealer for £8.81 inc. VAT new.

Not worth getting second hand from ebay as the price is nearly the same as a new one.

[RichardW]

The wiring diag shows a 5 pin, so the Halfords one should be OK if the pin layout is the same (should be) and the blade sizes match (probably - not much difference between 35 and 40A. I'd go for it if Halfords is a lot more convenient than a Cit or Pug dealer.

[niallmoran]

Just to get things back up and running I grabbed the Halfords relay and it seems to work fine...I'll probably get the proper one though as the Halfords one doesn't have the wee clips at the side so slightly less secure and obviously rated a bit too high (does this matter - do they have internal fuses?)

Thanks for your help chaps - saved me many hours of head scratching

[Hell Razor5543]

As far as I know vehicle relays don't have fuses (they would rely on the normal vehicle fuses). However, the rating is for the level of amperage they can safely handle. Normally a relay with a higher amperage than required is less likely to fail over a long period of time, as they are under less of a strain.

[Paul-R]

A relay with a higher capacity will work fine. Wottle do a lottle do a little.

Relays are generally not fused. In fact it's been years since I've seen one. I found one on a Renault Espace in a scrappy in 2011 when I needed such a device to wire in an accessory on the old Xsara. The fuse was a standard blade type and plugged into the relay body externally. Not internal at all - I don't think such a thing exists.