front fan help

Technical questions and answers about the Mazda Bongo

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murphy

front fan help

Post by murphy » Sun Jun 27, 2010 9:16 pm

My fan has stopped working - but following instructions in member factsheet fan runs with power directly attached.

i have removed the resistor and it looks ok - no sign of burning - so with this removed should the fan run ?

or do you need to short some cables...

is there a way of testing before spending money on a new one I may not need..

thanks
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missfixit70
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Re: front fan help

Post by missfixit70 » Sun Jun 27, 2010 9:19 pm

Have you checked the factsheet on repairing the resistor pack? links in the FAQ posted above.
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murphy

Re: front fan help

Post by murphy » Tue Jun 29, 2010 8:11 pm

yes factsheet says to replace the resistor if the motor runs only when on max setting.

my fan motor does not work on any setting - yet powering it directly from battery its ok.

Could it still be the resistor - at £80 a go I would like to know if there is a way of testing

could something else stop power to the fan ?
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missfixit70
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Re: front fan help

Post by missfixit70 » Tue Jun 29, 2010 8:15 pm

There's a factsheet on checking/repairing the fan speed resistor, all links in the FAQ - http://www.igmaynard.co.uk/bongo/forum/ ... 43&t=28727
Worth checking to see if there's voltage getting to the resistor controller pack, also there are relays behind & below the driver side headlight, also check the fuses, listed in the fuses factsheet.
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missfixit70
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Re: front fan help

Post by missfixit70 » Tue Jun 29, 2010 8:30 pm

Same question asked here - http://www.igmaynard.co.uk/bongo/forum/ ... =5&t=37740 probably best to lock this one to prevent confusion.
You can't polish a turd - but you can roll it in glitter.
murphy

Re: front fan help

Post by murphy » Tue Jun 29, 2010 9:03 pm

thanks for these -

so it says that if the resistor has broken fan will still operate at full power only.

If mine does not operate at full power and fuse is ok what then ?

previous post says if relay has gone air con fan doesn't work.

my air con fans come on ok.

fan motor works ok when directly powered
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Re: front fan help

Post by g8dhe » Thu Jul 01, 2010 6:24 pm

Looking at the circuit there are three obvious possibilities;

One the relay isn't operating to turn the Fan on at all, or secondly the left most fusible link has blown (in the pack) or if the resistor pack isn't fitted then the Fan won't turn at all of course.
Geoff
2001 Aero V6, AFT, full side conversion.
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mikeonb4c
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Re: front fan help

Post by mikeonb4c » Thu Jul 01, 2010 9:10 pm

murphy wrote:thanks for these -

so it says that if the resistor has broken fan will still operate at full power only.

If mine does not operate at full power and fuse is ok what then ?

previous post says if relay has gone air con fan doesn't work.

my air con fans come on ok.

fan motor works ok when directly powered
Weird cos I had read that too but when mine packed up t'other day the fan didn't work at all and the aircon would only work when fan setting was at number 1 position. Turned out all tabs on resistor had de-soldered (I suspet it must all depend on which tabs have de-soldered). Very simple to fix though if you can wield a soldering iron
murphy

Re: front fan help

Post by murphy » Sun Jul 04, 2010 3:27 pm

thanks for advice -

can you tell me if there is a way of bypassing the resistor pack - to isolate that as a fault.

ie shorting it ...

i put a volt meter on it and none of the three input pins has voltage though
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Re: front fan help

Post by mikeonb4c » Sun Jul 04, 2010 7:46 pm

murphy wrote:thanks for advice -

can you tell me if there is a way of bypassing the resistor pack - to isolate that as a fault.

ie shorting it ...

i put a volt meter on it and none of the three input pins has voltage though
Not tried that. Easy enough though (using factsheet, and it is VERY easy) to open up resistor and you will see at once if (some) tabs have desoldered. I'd approach the problem that way personally. Good luck 8)
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Re: front fan help

Post by g8dhe » Sun Jul 04, 2010 9:43 pm

murphy wrote:i put a volt meter on it and none of the three input pins has voltage though
There are 5 pins in all, and when the relay is operated with the switch set to LOW, then all of the pins, other than the LOW one, should have a a small voltage on them I would guess 2-6 volts.
If None of them have a voltage on then either the left hand fuse has melted, or the relay isn't operating - my bet would be on the fuse!
Geoff
2001 Aero V6, AFT, full side conversion.
murphy

Re: front fan help

Post by murphy » Tue Jul 06, 2010 9:53 pm

thanks to everyone who contributed to assist me.... ran of options now for me.... can anyone recommend a bongo friendly garage or person in hertfordshire ( st albans) i can take it to... don't really want to hand it over to my local garage which have been good with mechanical issues but they may struggle with this .......

cheers
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Re: front fan help

Post by johnny7 » Tue Jul 06, 2010 10:19 pm

I had a similar problem to this, my resistor pack blew all the soldered connections but not a fuse. Fitted a new resistor pack and it did the same thing, obviously a dead short but still did not blow a fuse. Turned out the fan motor was seizing in its bush it was stiff to turn by hand,I stripped the motor, cleaned the spindle, oiled it and after resoldering the connections all is now working fine.
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Re: front fan help

Post by g8dhe » Wed Jul 07, 2010 9:48 am

johnny7 wrote: my resistor pack blew all the soldered connections but not a fuse.
The "soldered" connections ARE the fuses - thermal fuses! They use a slightly softer solder mix which melts at a given temperature. The fuses in the boxes are there to protect the wiring not the devices themselves, they won't go until you have a wiring short. Motors are quite difficult things to fuse, in normal operation they will draw several times the average current at start up, so any form of normal fuse will blow at start up if it is rated to protect the motor during normal running, however if you rate it for start-up then it will never blow given a fault during running :(
Hence the use of the thermal resistors connected with the speed limiting resistors that get hot in normal operation.
Geoff
2001 Aero V6, AFT, full side conversion.
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