Hi,

Previously my climate control used to work but the fan speed was all over the place and often stuck on minimum regardless of what I set it to.

More recently, however, it doesn't work at all for either heating for cooling, even if it's set to maximum. I was looking at a post (called air con/heat just stopped working - unable to link to it), and tried phil0254's suggestion in that post, but nothing happened after 10 minutes - no radiator fan spin.

Note that I don't know where the heat pipes are for the aircon, so I couldn't check if they were heating/cooling.

Does anyone have any suggestions of what could be wrong/any further diagnostics I could do?

Thanks,
Hamish

Not sure from your description, usually if there is an electronic fault in the system the display will flash the temp selected to show the fault, however it could be something that the system can’t test, ie the blower motor has packed up.

Or the system thinks everything is working fine and another component isn’t recording a fault like the PW Module that controls the fan on climate control cars

Hmm, okay.

I have tried doing some diagnostics like checking the fuse for the compressor, taking the fan out and cleaning it - some leaves but nothing serious - but to no avail so far.

Next up I'm going to take a multimeter to the connectors and try to run the fan off batteries to see if it spins.

That's interesting, because I have noted that when I set the speed to 0 it sometimes flashes. Is that normal, or indicative of a fault? I don't believe it's done it any other time.

What is the PW module? Can I check another fuse for that?

Hamish

Okay, so the fan works, but there is no power coming through the connectors - I'm fairly sure it's a loom issue at the moment.


Can anyone recommend a garage somewhere in/near Poole/Bournemouth that can look at the electrics for this?


Thanks,
Hamish

PW module is “pulse width” modulation, basically it takes the 12V feed going to the battery and turns it on and off rapidly to make the fan spin at different speeds.

The voltage to the fan is therefore an AC not DC signal so testing dc voltage with a multimeter won’t work.

It’s a common problem that these modules fail with older fiats.

It’s easy to check a loom, put a multimeter on resistance on either end of the wire.

Okay, so I checked again with AC mode, and I can confirm that (at full power) there's ~16V on MAR, and ~24V with the ignition on. Does that sound reasonable?

The fan still isn't spinning though even though there is power. I don't know what the other connectors going into the fan do (two largish, one very small with green wires) - should I check them as well?

Hamish

I have to disagree with Andy this time: it is still DC even if rapidly toggled ON/OFF. AC mode on multimeter will give erroneous readings.
The correct way to evaluate a PWM is to hook an oscilloscope and check the wave form, OR use an old style "needle" Voltmeter whose inner coil will "see" the mean voltage resulting of the PWM...

BTW it is very possible that the PWM module needs a load in order to start working so it might not show output if not connected !


BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

That makes sense - it's why I started with DC, but that didn't read anything. I don't have either of those things, unfortunately.

At any rate, thanks both of you for your help .

I don't really have that much time to diagnose/fix this, so to re-iterate, does anyone know a good garage around Bournemouth or Poole that can fix this for me?

Hamish

All fixed, and I found a good garage on Mill Lane in Wimborne.

It turns out one of the plugs had melted and wires corroded, so I needed a new connector. Not sure how I didn't spot this, but it's fixed now so all is good. Thanks for all your help.

Haaaaa, the notorious corroded/melted connector ! Anyway, thanks for the update

BRs, Bernie