Front Fan .. Wits End

[Dangermike]

Hello all,

I know this is a subject that has been exhausted quite a few times, and i think i have read every post about it!,

So bought a Bongo recently, and the previous owner said the fans and aircon worked before it was stored for 6 months,

So Me thinking it would be a simple fix, i pulled the transistor (Climate control version) and replaced the transister inside, as well as soldered down the sprung metal that had unsoldered.


This did not work,

I checked all fuses and all are fine

I located the earth point behind the drivers headlight, this was no longer attached and fully rusted, so i stripped an crimped each wire and then created a new solid earth point,


This did not work

I located the relay on the passenger side and shorted out the Purple and Red wire, (No and Com) this didnt seem to work ( i might have done this wrong)

So im not sure what is next or the diagnosis i can do to fault find, it,,,, ive heard that the control panel sometimes need resoldering... but cannot see any info on this

i have so far found 2 faults and fixed them both with no help!

Also found a red cable with blue stripe that was corroded and detached from a white connector , and repaired that,,, and not sure what it was for

[g8dhe]

Have you tested the Fan itself direct to battery just for testing ?
There are two relays associated with the air con fan:
Second from the front one or 3rd from rear (depends on how many options fitted!) G3-05 on the nearside wing, this only controls the Max fan speed when set to level 4.
Main power to air con fan 3rd from front on the offside wing G3-07, more likely to be your problem one.

[Dangermike]

Thanks Geoff,

I will try that relay tonight,

Yup i tried the fan directly to battery and it worked fine,

The relay on the offside seemed to have different colour wiring to the diagram i read ( Purple , black and 2 reds)

Will Definitely check the main power one,

Seriously how many faults are there???

Any idea what that red wire that was corroded was for?

[g8dhe]

You haven't said what year of vehicle, there have been some changes after 1999 which is the limit to the ones on line. The basic circuits haven't changed a great deal but I can't comment on loom colours!

[Dangermike]

Hi, apologies it’s. 1997 model

So located the main relay on the near side,
Connections looked good,
Shorted out the NO and COM. As I believe that’s how you bybass it, and still no joy,

It had 2 thin green wires in the 2 Coil connections and 2 blue in the NO and COM

Will study the wiring diagram tonight to see if I can make sense of it,

If it helps the rear can seems to be working fine,
Just the front fan that doesn’t operate at all

[g8dhe]

The one on the nearside only sets the Max speed, its the one on the offside that switches it on/off.

[Dangermike]

Hi,

Sorry for the confusion....
It was the Offside I was testing, brain got confused...
drivers side to the left of the battery
3rd from the front.

Shorted across the 2 Blue cables, NO and COM and nothing happened. There is power going into the one of them.

Will try to follow the cables now that I have an understanding of the drawings,

[Dangermike]

Ok so I have some good news! After doing a lot more tests I found that the plug to the fan was getting the 12v when needed but the fan wading working, then found that it was very corroded and messy in the plug on the fan side so I cleaned it all up and viola! We have fan!
But only only on full speed, speed 123 don’t work .... now this is strange as I have already replaced the transistor component and soldered down the spring fuse

Can I confirm I was supposed to solder it down?

[g8dhe]

If you have run the fan whilst it was still stalled then you have most likely toasted the transistor again! Try checking each junction with a meter before replacing however.
Its a long time since I looked at mine but your image seems to imply it should be soldered down.

[Dangermike]

Hi , thanks yes I think it may be gone again
It’s supposed to be a NPN
However I’m getting a resistance reading with the negative probe on base and positive one emiter also getting a reading across both emitter and collector....

Annoying! Paid more to get the part quickly last time as well!

[Dangermike]

So update, and problem solved,
Found that one of the legs from the transistor snapped when I put it in the casing, all fixed now and all fans running!

Just taken it to Kwik-Fit to get regased, luckily I read a few topics before as they had no idea what gas or oil to put in!

So now it is being filled up! They mentioned it was completely empty!

[g8dhe]

Ah good to hear!

[Dangermike]

So fans ran perfectly for 2 months,
Then decided to stop working again,
Straight Way thought it was corrosion in the plug, so tried to clean it up and ended up removing the plug and crimping the wires together for now and I’ll replace the plug when I get home ( on holiday) unfortunately this did not solve it, before I left I also fitted a new thermostat as I had another spare, this didn’t help,

Haven’t had a lot of time to investigate but measured the voltage at the fan plug and it’s only getting 3v ish .... so thinking possibly earth? If it was a relay I expect it to be 0v?

[Dangermike]

So an update if anyone is reading this,

Measured the voltage getting to the fan relay and transister, and it was all about 3v
So went back to the earth point I repaired last time and found that the connector had corroded and broken again!

I re connected the earth and all seems to be working now,
I bought a new bus bar, to fit as the connectors on that earth are all badly coroded!

Will show pictures once done

One other thing though, the first 3 fan settings are all pretty much the same ( a light breeze)
Is this to do with the transistor? As I have replaced it already!

[g8dhe]

Could easily be, you may find that the transistor has gone leaky so pretty much constant speed until the top speed when the relay bridges out the transistor itself.