Fan NOT turning off

[WazzaL]

One of my fans does not appear to want to turn off. Even having remove the key, and no I don't have the mod-wise mod..

Thinking it may be a relay, but has anyone experienced this before and able to offer any ideas as to what else it could be?

[Ribol]

Not experienced it but I would swap the two fan relays over(next to each other).

If the problem moves to the other fan then it is the relay, if it doesn't then it's the wiring.

[GreenV8S]

Assuming you don't have a fan override switch fitted (worth checking if there's any possibility!) it will be a stuck relay, or stuck otter switch. You can find out which by pulling a wire off the otter switch.

[Ribol]

GreenV8S said:

Assuming you don't have a fan override switch fitted (worth checking if there's any possibility!) it will be a stuck relay, or stuck otter switch. You can find out which by pulling a wire off the otter switch.

Only one staying on?

[That Daddy]

If the relay is sticking it is not going to be affected by the otter switch,as already said swap the relays to pin point the culprit

[spend]

You should be able to swap the horn relay if you don't have a spare. Be very careful swapping over a crap relay it may have odd effects depending on the way twin fan relays have been implemented, I've seen several ways and have no idea how you can tell without looking at the back of the fuse box.

Dave

[Ribol]

spend said:

Be very careful swapping over a crap relay it may have odd effects depending on the way twin fan relays have been implemented.....

You're not going to get two fan relays in the same fusebox with different pin arrangements - on any car. Swapping them over is not going to cause any problems at all.

spend said:

.....I've seen several ways and have no idea how you can tell without looking at the back of the fuse box.

You take out the relay that is working, check how it works then fault find the one that has the problem - easy.

[spend]

Ribol said:

spend said:

Be very careful swapping over a crap relay it may have odd effects depending on the way twin fan relays have been implemented.....

You're not going to get two fan relays in the same fusebox with different pin arrangements - on any car. Swapping them over is not going to cause any problems at all.

spend said:

.....I've seen several ways and have no idea how you can tell without looking at the back of the fuse box.

You take out the relay that is working, check how it works then fault find the one that has the problem - easy.

If the first relay is switching the second one your logic fails miserably IMHO.

Dave

[Ribol]

spend said:

Ribol said:

spend said:

Be very careful swapping over a crap relay it may have odd effects depending on the way twin fan relays have been implemented.....

You're not going to get two fan relays in the same fusebox with different pin arrangements - on any car. Swapping them over is not going to cause any problems at all.

spend said:

.....I've seen several ways and have no idea how you can tell without looking at the back of the fuse box.

You take out the relay that is working, check how it works then fault find the one that has the problem - easy.

If the first relay is switching the second one your logic fails miserably IMHO.

If you have two fans on a car, two relays in the fusebox both with their own supply running off one otter what kind of a muppet would wire them up as you have suggested?

[spend]

Ribol said:

If you have two fans on a car, two relays in the fusebox both with their own supply running off one otter what kind of a muppet would wire them up as you have suggested?

Several dealers & indies I believe, to reduce the shunt from the fans starting as I understood it. We don't live in a perfect world

Dave

[Ribol]

spend said:

Ribol said:

If you have two fans on a car, two relays in the fusebox both with their own supply running off one otter what kind of a muppet would wire them up as you have suggested?

Several dealers & indies I believe, to reduce the shunt from the fans starting as I understood it.

I didn't realise electricity moved so slowly

[spend]

If someone at sometime has been 'supersmart' and installed a capacitor to delay the 2nd fan op (and give 'run-on') you could be getting into all sorts of complicated diagnosis. This has little to do with our opinions of the possible implementations - just an appreciation that they have been done to some cars Hell he might even have 2 otter switches??

Dave

[Ribol]

spend said:

If someone at sometime has been 'supersmart' and installed a capacitor to delay the 2nd fan op (and give 'run-on') you could be getting into all sorts of complicated diagnosis. This has little to do with our opinions of the possible implementations - just an appreciation that they have been done to some cars Hell he might even have 2 otter switches??

I am sure there might be someone out there that might actually believe you - I know better

[WazzaL]

No. Car still standard. no strange capacitors or suchlike.

Where would be the best place to get a replacement relay?

[Ribol]

WazzaL said:

Where would be the best place to get a replacement relay?

Have you actually tried swapping the relays as suggested by a few above?

[JonathanT]

Ribol said:

GreenV8S said:

Assuming you don't have a fan override switch fitted (worth checking if there's any possibility!) it will be a stuck relay, or stuck otter switch. You can find out which by pulling a wire off the otter switch.

Only one staying on?

I'm watching this carefully as I've a long term undiagnosed problem with mine that sounds similar (fans come on with ignition off even if engine stone cold).

For me only one fan comes on, and the other comes on when I swap the relays. Now to work out which way round the relays are and replace that with my spare....??

Thing is, both these relays are (a year ago) "new" replacements already....

Edited by JonathanT on Wednesday 28th November 17:31

[spend]

Wires charred & fused together is unfortunately not so uncommon, I would be inspecting the underside of the fusebox if I was you. I do have have a modicum of safe vs sorry

Dave

[WazzaL]

Yes, have swapped relays over and the problem reverts to the other fan..

Misterious!! - Think it might be a knackered relay.

So, popped down to my local Halfrauds to find 'they stock stock relays'

Hence, the post where best to buy an appropriate relay.

So any ideas??

[spend]

Stock (they are the most the common) will work, if you are specifically after the colour coded siemens items? Rovers used them as well ~ I've always had loads from Rovers in scrapyards (one stop shopping - you can raid fords & vauxhalls for the door & wiper timers)

Stick a spare in an unused socket whilst you are at it

Dave

[WazzaL]

Very interesting.

Looks like a trip to a local scrap merchant to pilfer a fan relay from a Rover then.

Fantastic.