Radiator fans not working

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

rita
Supreme Being
Posts: 3284
Joined: Tue Sep 15, 2009 7:11 pm

Re: Radiator fans not working

Post by rita » Mon May 07, 2012 12:42 pm

quote="haydn callow"]I did not go the ebay route....in the end I considered them to be poor quality and so went for the ones from Chine which turned out to be little better.....you win some/lose some.....
they were cheap and cheerful and would probably have done the job ...but I didn't feel I could give a warranty as I do with all the products I do sell.[/quote]


Hi Haydn,

People getting ripped off is on of my pet hates,is the eBay complaint still pending?,how many units were in the Batch.All might not be lost... :wink:
User avatar
haydn callow
Supreme Being
Posts: 5772
Joined: Mon Jan 08, 2007 9:50 pm
Location: Somerset
Contact:

Re: Radiator fans not working

Post by haydn callow » Mon May 07, 2012 3:28 pm

I didn't use ebay
http://www.coolantalarm.co.uk
Developer of the Mazda Bongo Coolant loss Alarm
Also BMW Clocks
gazza

Re: Radiator fans not working

Post by gazza » Thu May 24, 2012 10:03 pm

Hi Swampy, just reading through your post, did you ever sort this issue out?
I have had the same problem.
I had the head changed due to cracking, then could never get the fans to kick in even after giving it stick until the needle was at max (I too have the cluster resistor mod).
I have been running round with the low speed fans running as soon as the ignition is on.
All 3 fans run when I ground the signals at the ecu.
resistnace values from temp sensor look good.

It runs great with the fans on all the time, but I would like to get to the bottom of the issue.

Did you sort your van?
Garry
User avatar
Northern Bongolow
Supreme Being
Posts: 7713
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: Radiator fans not working

Post by Northern Bongolow » Fri May 25, 2012 4:50 am

he said it was the fan switch, he fitted another gen mazda one, |£36 from mazda or ian sells them. dont bother with coppies they are crap.
they usually fail when the grey plastic end that the wires clip into starts to wobble, between the plastic and brass probe.
you will need to bleed it if you take it out.
Alkers
Bongolier
Posts: 219
Joined: Fri Nov 20, 2015 4:33 pm

Re: Radiator fans not working

Post by Alkers » Thu Jul 28, 2022 2:26 pm

Sorry to bump a very old thread!

I've just had my radiator replaced and van is good to go but the garage (not bongo specialist but getting there!) havent been able to get the radiator fans to operate.
He said he had it up to 95C (not sure how he measured it).
Is this normal or is something wrong? Fans are working fine when he puts 12v to them. Whats the likely fix if something is broken - is it the temp sensor underneath the handbrake or elsewhere?
teenmal
Supreme Being
Posts: 3656
Joined: Thu Mar 27, 2008 6:08 pm
Location: north lanarkshire

Re: Radiator fans not working

Post by teenmal » Thu Jul 28, 2022 3:35 pm

He probably measured the temp with a thermometer (digital) if you disconnect the plug on the sensor with ignition on the fan /s should run.

If he goes on Youtubby there are loads of vidios showing how to test it. Probably the temp was not high enough to activate fan.
teenmal
Supreme Being
Posts: 3656
Joined: Thu Mar 27, 2008 6:08 pm
Location: north lanarkshire

Re: Radiator fans not working

Post by teenmal » Thu Jul 28, 2022 3:38 pm

Alkers wrote: Thu Jul 28, 2022 2:26 pm Sorry to bump a very old thread!

I've just had my radiator replaced and van is good to go but the garage (not bongo specialist but getting there!) havent been able to get the radiator fans to operate.
He said he had it up to 95C (not sure how he measured it).
Is this normal or is something wrong? Fans are working fine when he puts 12v to them. Whats the likely fix if something is broken - is it the temp sensor underneath the handbrake or elsewhere?
What engine ??
Alkers
Bongolier
Posts: 219
Joined: Fri Nov 20, 2015 4:33 pm

Re: Radiator fans not working

Post by Alkers » Thu Jul 28, 2022 3:39 pm

Sorry - 2.5TD, I've no idea whether the fans were working previously or if indeed there is any issue.
My Aircon condenser and rad have been removed the van tends.to run quite.cool
David41r
Apprentice Bongonaut
Posts: 3
Joined: Thu Mar 23, 2023 4:11 pm
Location: Sussex

Re: Radiator fans not working

Post by David41r » Tue Mar 28, 2023 10:26 am

Sorry to re-open this thread.I would welcome some advice on how to track down a problem with my Y plate 2L petrol bongo with digital AC.

Driving in traffic last weekend (Mid March and chilly) and noticed the temp gauge climbing. Usually it stays firmly resting on the left hand end stop unless working hard in warm weather. Turns out the radiator fans have stopped coming on. I have been through the forum for hints and tips and done the following.

1. Turned AC on and off. No change.
2. Manually turned the fans and then applied 12v. They are free and run on a direct supply.
3. Tested all the fuses in the drivers box and the one in the middle under the bonnet. All fine.
4. Pulled the relays and tested that they click with power, they do. (the four in front of the car bat, the two in the engine bay fuse box and the front two on the passenger side wing.)

Its in for its MOT today and they mechanic will make sure the AC is gassed and look to try re-gassing if needed.

The next step is to swap over the relays in front of the bat and see if they move the problem.

Questions.
Can anyone give tell me which relays are for the fan? I can't find a diagram.
Any other diagnostics tests?
I can see a data port under the glove compartment. Is this useable?

Any suggestions or pointers would be much appreciated.

Many thanks, David
User avatar
g8dhe
Supreme Being
Posts: 10179
Joined: Sun Apr 13, 2008 10:06 pm
Location: Worthing, West Sussex.
Contact:

Re: Radiator fans not working

Post by g8dhe » Tue Mar 28, 2023 11:04 am

The diagrams for the fan circuits are below followed by the locations;
Cooling system FE-E-1.jpg
Cooling system FE-E-2.jpg
The wiring diagrams are still on line here http://www.g8dhe.net/bwm/ but you need a browser that can handle the old Adobe Flash system
The only browser that can still handle the files is the Chinese based one that was allowed by Adobe to continue using the Flash system which can be downloaded here https://pdds-cdn.ucweb.com/8-0/UCBrowse ... 10215).exe

They go to great lengths to try to get you to download various other versions, which don't still support Flash, I have given you a link to the exact spot I downloaded but watch out for spurious links to other types of UC Browser! It works fine but I can't say what else might be built in so use at your own risk 😉
Geoff
2001 Aero V6, AFT, full side conversion.
Image Spherical Visions
David41r
Apprentice Bongonaut
Posts: 3
Joined: Thu Mar 23, 2023 4:11 pm
Location: Sussex

Re: Radiator fans not working

Post by David41r » Wed Mar 29, 2023 10:18 am

Thanks for the diagrams. Really helpful. I think the issue is the emu not sending a switch on signal to the relay. Since the AC does have gas pressure and the temp gauge is registering. I think the issue may be the emu itself.
User avatar
g8dhe
Supreme Being
Posts: 10179
Joined: Sun Apr 13, 2008 10:06 pm
Location: Worthing, West Sussex.
Contact:

Re: Radiator fans not working

Post by g8dhe » Wed Mar 29, 2023 11:26 am

Check to see if the coolant temperature sensors are OK before suspecting the ECU itself.
Geoff
2001 Aero V6, AFT, full side conversion.
Image Spherical Visions
David41r
Apprentice Bongonaut
Posts: 3
Joined: Thu Mar 23, 2023 4:11 pm
Location: Sussex

Re: Radiator fans not working

Post by David41r » Fri Mar 31, 2023 12:45 pm

Thanks for the suggestion.The coolant temp sensor does appear to be working. It has an impedance and when i touch a 4.5v battery across the terminals the engine note rises but the fan does not come on. (also reversed polarity and the engine note dropped.)

So my thinking is.

The circuit to power the fans is fine - fuses good and relays ok.
The sensors to the EMU are good and the EMU is responding to the inputs in some way.
The signal to switch on the fans is not getting to the relay.

So either a bad connection between the EMU and the relay or a bad component in the EMU output stage. Had a poke around in the EMU wiring, looks in good order and not for the faint hearted. I have ordered the wiring manuals CD and will try to find the control output pin to test the continuity from the fan control output.

So another question.

I could hard wire the fans so they are on all the time the ignition is on. Would this be a problem? In the summer the fans will run full time anyway due to the Air con?
Post Reply

Return to “Techie Stuff”