Technical Fan Heater DOESN'T work on position 4

[Burstner685]

Hi

I have the opposite problem to most people, in that the fan heater works on all positions, except MAX (position 4). Is this still likely to be the heater resistor?

Thanks.

 

[Communicator]

The simple answer is that it is most unlikely to be the resistor.

Please see the sticky at the top of the Ducato home page.

Details of base vehicle, including options as applicable, are essential.

 

[Anthony489]

Hi. I'm going to assume your base vehicle is the 2006 onwards X250 Ducato.


In the full speed fan setting, current flows from Pin 5 of the resistor pack O030 via a black ** wire to Pin 5 of the dashboard speed switch H081. The resistor pack is mounted above the footwell in the fan casing. The speed switch (on full speed) shorts between its Pin 5 and Pin 1, which is grounded. So the first thing to check is the black wire, and the connectors at both ends. Any sign of discoloration or distorted plastic means a bad connection which has overheated. The second thing to check is the switch. If you remove the switch loom connectorand put a link between Pins 5 and 1, the fan should come on at full speed. The fan on full speed draws quite a high current, typically 20 or 30 Amps, so these connections must be 100% OK.

All the other parts of the fan and its control are used on the lower speed settings, so I assume these are OK.

** It's not unknown for Fiat to change wire colours.

 

[Burstner685]

Sorry for lack of info, it’s a 2005 X244 2.8 JTD chassis in a Burstner A Ckass Motorhome RHD. Was working fine a couple of days ago.

 

[Communicator]

I am sorry but air conditioning is a relevant option/accessory.

As your vehicle is a motorhome, I will assume that aircon is fitted.

The following link is to a diagram for the aircon installation in an x244 Ducato.
http://4cardata.info/elearn/244/2/244000001/244000003/244000005/244001985

If you look at the lower RHS of the diagram H081 is the fan control switch, and N085 is the fan.

Position 4 of the switch connects via a grey/red (HR) wire to terminal 3 of relay J041. Terminal 4 of this relay connects to the fan motor.

It follows that relay J041 must be operated for speed 4 to be obtained.

Based on long experience of working with relays, I tend to be sceptical when they are the prime suspect without any evidence, however failures can occur and as Anthony489 has stated, the fan motor draws a considerable current.

As I believe relay J041 is located under the plastic cover at the rear of the engine bay, corrosion of the connections should be considered.

eLearn shows a group of four relays, with J041 being second from your right, when looking into the engine bay from the front.


Fiat wiring colour codes are available via an internet search.

 

[Burstner685]

Thanks for that valuable information Communicator, yes air con is fitted. Interestingly, air con stopped working at the same time the MAX position stopped also. The light on the air con switch is illuminated. I'll check the relays.

 

[Ocwobio]

Mark, I can't claim to know where the relay is, sorry, there AFAIK some in the ebgine bay fusebox, the nearside fusebox, don't know about the offside- can't recall seeing them there tho'. Just a thought- had it stopped working before you started the CC work? If it stopped after, maybe the wiring in the dash(is the black connector thick wiring significant here?) has been disturbed or damaged. I would be inclined to check the fan rotary switch first, as it carries a good load on 4. My old Laguna suffered thus, and it was a well known weak spot on that car. The damage was apparent as soon as the switch was removed, scorching and distortion. Just thought tho'- is the load in fan 4 greater than the combined load of the motor + any in circuit resistors, or the same or less? If it's more, I would go straight for the switch.

 

[Communicator]

I think that Ocwobio may have pointed at the fault. I am not an expert on Fiat aircon, but connector D018B pin3 carries one of two alternative supplies to the fan motor. This supply direct from 40A maxi blade fuse F05 in the engine bay fusebox, is used when fan speed 4 is selected.

 

[Anthony489]

Hi

Thanks to the schematic posted by Communicator, here is a revised summary of how the fan works in your vehicle.

On Speeds 1, 2 and 3, the +12 V supply comes via Relay T12, Fuse F55 (30A) in B002, Relay J022 Pin 5 and then out of Pin 6 to the "Hot" side of the Fan motor. The "Cold" side of the fan motor goes via one or more resistors in the resistor pack O030 and the speed switch H081 to ground. Relay J034 allows the Aircon to override the switch if it is set to off, and force speed 1.

On Speed 4, the 12V supply comes from the battery through Fuse F05 (40A) in B001, Relay J022 Pin 4 and thence to the "Hot" side of the Fan motor. The "Cold" side of the fan motor goes through a White/Black wire to Pin 4 of Relay J041, through its closed contacts and out via Pin 3. This connects via a Green/Red wire to Pin 5 of the speed switch H081 and through it to ground. The fan switch in position 4 also grounds the coil of Relay J022, switching the +12 V supply from Fuse F55 to Fuse 5.

Relays J041 and J022 should both have their coils energised in Fan speed 4. This relies on the presence of a +12 V supply from the ignition key controlled INT/A line via Fuse F31 (10A) in B002, which ALSO provides the +12V supply to the air con. All these wires are Light Blue/Red.

If you have managed to stay with me this far, a failure of speed 4 AND air con points to a lack of +12V supply via Fuse F31.

 

[Burstner685]

It's very interesting. My celebration at the successful install of cruise control was, perhaps, premature! I'll have a look around tomorrow and get the multimeter out. I'll report back with my findings. Thanks everyone for your input.

 

[Burstner685]

OK, couldn't sleep on it, so just checked. F31 is good and there is a 12v supply to it. I'm sure I checked the correct fuse, top left hand corner in fuse box on passenger side (RHD), 10a.

 

[Burstner685]

In fact I've checked all the fuses in the passenger side fuse box (just to be sure) and they're all good.

 

[Communicator]

Please can you check continuity of MAXI blade fuse F05 in the engine bay fusebox? I have references to this fuse being either 30A (green), or 40A (orange).

With the main input cable and maxi blade fuses on the right (take care) F05 should be third down.

Also there is pertinant error in eLearn. This relates to relay J022. It might work better if the contact designations 30, 87A, and 87 were rotated anti clockwise, to match the rest of the drawing. (Bosch terminal notations 30 = common, 87 = NO, and 87a = NC.)

 

[Burstner685]

F05 which was Orange 40a is good, difficult to get the probes in, but I don't think there is power to this fuse, with ignition on and fan in P4.

 

[Burstner685]

I should add that this fault with fan in max position and air con not working coincided with fitting the cruise control. I can't think that I've upset any other wiring, but it may help?

 

[Communicator]

I should add that this fault with fan in max position and air con not working coincided with fitting the cruise control. I can't think that I've upset any other wiring, but it may help?

I am aware that you recently added cruise control, and appreciate your thanks on the appropriate thread.

I had considered the following possibility previously, but did not wish to appear insulting.

Fuse F05 supplies the fan motor on speed 4, via relay J022. Between fuse F05 and relay J022 there are two connectors, D018B pin 3 (cruise control control fitted to pins 1, 2, 5, & 6). From my memory pin 4 controls the aircon compressor clutch. Please check that D018B is fully latched, and thick red wire on pin 3 is OK.

The other connector in the fan motor circuit is D161A, which is part of the aircon option. From eLearn it is a 7 way connector with 2 large pins, one of which, G, takes the thick red fan motor wire. Location?? eLearn is hard to decipher in this respect, but could be buried central dash area, or similar in engine bay.


For details see the RHS of the diagram linked to by me earlier in this thread.

If you have any doubt as to the continuity of fuse F05, remove for a continuity test, or at least, visual inspection.

 

[Burstner685]

OK Communicator, get ready to despair! Perhaps you should have just appeared insulting. What a stupid oversight I have made, which I am ashamed to admit, but considering your involvement in my problem, I must come clean. I forgot to reconnect D018. It must have been due to the excitement of successful CC installation.

 

[Communicator]

So all OK now. Inferred apology accepted.

May I take this opportunity to add a further word of caution for anyone using eLearn wiring diagrams for the x244 series Ducato.

The diagrams contain many errors. As an example the wiring for non aicon heater fan will not work as shown on diagram E6010. It needs considerable correction around the control switch to show the correct wiring connections.

 

[Ocwobio]

Haha, glad you got a result Mark. Reminds me of a certain guard who detched and engine from a train, and didn't let the air out of the ABP. Only to have it follow the loco out before the pilot tied on behind!

 

[Burstner685]

Communicator - of course, I should have apologised. Thanks for your input.

Ocwobio - Yes relieved to get it sorted.