Radiator fans..

For all those wiring gremlins we love, this is the place to discuss them.

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Zaphod
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Model: Excel SE
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Radiator fans..

Post by Zaphod »

Just fitted the new alloy radiator, and along with it the fans.. While I was doing this I dropped a socket in the headlight pod area so had to put the battery on to get it out (as the headlights are out it was easier to just raise them) I forgot to disconnect it after, and when I plugged the radiator fans in the drivers side fan came on, the passenger side stayed off (both were tested on the bench, both are working) is this to be expected with the ignition off and the expansion tank (and thus the low coolant level switch) on the bench?
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel
2007 BMW E92 320d M Sport

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Hawaiis0
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Model: Excel SA No 3
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Re: Radiator fans..

Post by Hawaiis0 »

Fans should not run until over temp.

Could the PO have rigged a bypass switch?

The otter switch, joined in between in the water hoses just behind top of the rad, is the thermal on switch.

edit just seen the comment on low level - going back to check

edit low level shouldnt affect the fan running. Both should go together when the 2 pole relay closes.

Check the fan relay is the correct type and not a changeover one.

edit fuses 22 & 23 are on each fan feed check them

Zaphod
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Posts: 60
Joined: Mon Aug 23, 2021 21:38
Model: Excel SE
Colour: Blue
Year: 1990
Location: Uffington

Re: Radiator fans..

Post by Zaphod »

Just found what appears to be brake fluid in the fan relay! Not sure how it has got there but it’s been in there some time judging by the corrosion.. but it seems to be the only one effected. However that still leaves the issue of only one fan running.. both do work, I have just checked again with the bench supply on the one that did not fire up, both fan fuses are fine as I swapped them over.. still the drivers side one working
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel
2007 BMW E92 320d M Sport

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Hawaiis0
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Joined: Sun Jun 30, 2013 18:39
Model: Excel SA No 3
Colour: BRG
Year: 1986
Location: West Oxfordshire

Re: Radiator fans..

Post by Hawaiis0 »

The brake fluid will most likely be congealed water.

That means the relay base is also going to be corroded.

Check for 12 volts at both fuses, that should confirm.

Each fuse is fed from a different relay pin

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Tanz
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Re: Radiator fans..

Post by Tanz »

Did it look like this - you need to find how the water is getting in.
Image
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Zaphod
Junior Poster
Posts: 60
Joined: Mon Aug 23, 2021 21:38
Model: Excel SE
Colour: Blue
Year: 1990
Location: Uffington

Re: Radiator fans..

Post by Zaphod »

It was a little like that.. the others around it are dry. No other signs or water ingress have been found, carpets are good
Of all the things I have lost I think I miss my mind the most...

1952 MG TD
1959 Austin Healey Sprite
1975 MG Midget 1500
1990 Lotus Excel
2007 BMW E92 320d M Sport

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