IF IT DOESNT RAIN IT POORS!! Cooling Fan issue

[swimmer27]

Hi All,
A search has only flagged up everything I have tried so perhaps the kind folk on this forum may of experianced the same thing.
Last week my main car twice let me down which I have put down to the integral fuel pump so being short of funds (Divorce) I decided to use my S2, did a 30 mile trip this morning and whilst in traffic near to home the temp gauge was heading for the red and there was no sign of the cooling fan working so once home I did the following.
1. Made sure the fan rotated ok and it does
2. Checked the fuse and all ok
3. pulled the two wires off the otter switch and short them together with the ignition on but stll no fan
4. Ran a wire from the battery directly to the fan and it sprang into life so the fan is working.
5. Switched the cooling fan relay with the headlamp relay (looked the same and had the same values on them) but still no fan.
6. Bridged the live and earth socket where the relay lugs push into the fuse box and the fan came on.
7. Checked all the connections to and from the fan.

The car has a fan override swith on the steering cowling but this too does not bring the fan on so I checked the feed from this switch to the otter switch and this is working ok.

So fellow S owners do you have any ideas where to go next, I suppose it's possible the headlight relay and fan relay are different, not sure how to test a relay.
When I shorted the two wires on the otter switch together although the fan refused to go the relay could be heard clicking.

I have looked at the TVR alternative parts list but the relays are not mentioned.

Thanks in advance

Edited by swimmer27 on Saturday 21st January 16:09

Edited by swimmer27 on Saturday 21st January 16:47

Edited by swimmer27 on Saturday 21st January 17:41

[rzrz]

Had the same in the past. Relay clicking but contacts not touching each other. Little bending and it was fine. Later replaced it.

Gr, Raoul

[tvrgit]

Number 7. Did you check the connector under the centre of the radiator? Fills with crud, corrodes - no contact, fan no worky. Connect up a bulb or voltmeter across the terminals, see if there's current reaching that connector.

I replaced my connector with a waterproof one, no more panics in traffic queues.

[swimmer27]

tvrgit said:

Number 7. Did you check the connector under the centre of the radiator? Fills with crud, corrodes - no contact, fan no worky. Connect up a bulb or voltmeter across the terminals, see if there's current reaching that connector.

I replaced my connector with a waterproof one, no more panics in traffic queues.

I can't see a connector underneath the rad so do you mean this black one in the centre of the photo? if so then yes this is clean.

[tvrgit]

swimmer27 said:

I can't see a connector underneath the rad so do you mean this black one in the centre of the photo? if so then yes this is clean.

Sorry yes, didn't notice yours was an S2 with the fan behind the rad.

What about those non-standard connection in your photo, between the black connector and the fan? They don't look to be in very good nick in that photo...

[phillpot]

That looks like a fuse holder?

They may not be the problem but I'd get rid of those crappy electrical connector blocks, not the best thing to use in such an exposed position (imho)

take a look at www.vehicleproducts.co.uk if you've got a few spare minutes

[Oldred_V8S]

I am away from the Bible at the moment so am looking at a rather bad copy of the wiring diagram, one which shows more than one relay connection numbered 87. I assume you do not have a multi-meter, if yes please let me know and we can do some more tests.

You can look at the relay and identify the corresponding connection numbers in the socket.

You should have 12 volts (supply) coming into the socket that 30 pin goes into.

When all is well and the relay is energised the 12 volts from the above pin should appear at the pin 87 socket (to the fan)

Pin 85 on the relay goes to ground via the otter switch, (grounds/energises the relay coil)
Pin 86 on the relay socket is a live feed to the relay coil.

So if you place a piece of wire between the following connections the fan should switch on:

30 to 87 (Bypasses the relay connection)
86 to 87 Bypasses the coil and the relay connection)

Like I say I am looking at a rather bad photocopy of the wiring diagram from the bible and a number of connection numbers look the same, so I have found a website that shows relay connections. You should ensure you understand what connections are what, these should be shown on the relay, also we all know that TVR don't always follow conventional rules.

If you feel unhappy doing any of this please seek assistance.

Cheers,

Paul

[swimmer27]

phillpot said:

That looks like a fuse holder?

They may not be the problem but I'd get rid of those crappy electrical connector blocks, not the best thing to use in such an exposed position (imho)

take a look at www.vehicleproducts.co.uk if you've got a few spare minutes

They look poor but are ok as when I removed the relay then bridged the live and earth where the relay pushes into the fuse box the fan kicked into life

Thanks

Edited by swimmer27 on Saturday 21st January 19:02

[tvrgit]

phillpot said:

They may not be the problem but I'd get rid of those crappy electrical connector blocks, not the best thing to use in such an exposed position (imho)

take a look at www.vehicleproducts.co.uk if you've got a few spare minutes

Ditto

swimmer27 said:

They look poor but are ok as when I removed the relay then bridged the live and earth where the relay pushes into the fuse box the fan kicked into life

Missed this in your original post. It's the relay.

[swimmer27]

Oldred_V8S said:

I am away from the Bible at the moment so am looking at a rather bad copy of the wiring diagram, one which shows more than one relay connection numbered 87. I assume you do not have a multi-meter, if yes please let me know and we can do some more tests.

You can look at the relay and identify the corresponding connection numbers in the socket.

You should have 12 volts (supply) coming into the socket that 30 pin goes into.

When all is well and the relay is energised the 12 volts from the above pin should appear at the pin 87 socket (to the fan)

Pin 85 on the relay goes to ground via the otter switch, (grounds/energises the relay coil)
Pin 86 on the relay socket is a live feed to the relay coil.

So if you place a piece of wire between the following connections the fan should switch on:

30 to 87 (Bypasses the relay connection)
86 to 87 Bypasses the coil and the relay connection)

Like I say I am looking at a rather bad photocopy of the wiring diagram from the bible and a number of connection numbers look the same, so I have found a website that shows relay connections. You should ensure you understand what connections are what, these should be shown on the relay, also we all know that TVR don't always follow conventional rules.

If you feel unhappy doing any of this please seek assistance.

Cheers,

Paul

Thanks Paul, yes I do have a multi tester so will have another look in the morning and then post results later as going out tomorrow. I think I connected my piece of wire between 86 and 87 then the fan came on.

Paul

[Oldred_V8S]

swimmer27 said:

Thanks Paul, yes I do have a multi tester so will have another look in the morning and then post results later as going out tomorrow. I think I connected my piece of wire between 86 and 87 then the fan came on.

Paul

OK if you connect a wire between 30 to 87 hopefully the fan will run. This will prove the relay is at fault or you have a problem with the otter switch or associated wiring, but you said

"When I shorted the two wires on the otter switch together although the fan refused to go the relay could be heard clicking."

So I think the wiring sounds OK.

Good luck let us know how you get on.

[v8s4me]

When you connected the fan directly to the battery I assume you connected it via the fan side of the long black connector? Did you check by feeding power to the loom side of that connector? I’ve got these connectors on my heated seats and so I know they aren’t very good and definitely not waterproof. Also use your multi-meter to see if power is getting to the loom side part of the connector.

[Oldred_V8S]

v8s4me said:

I’ve got these connectors on my heated seats

Heated seats!!!!!

[swimmer27]

Oldred_V8S said:

OK if you connect a wire between 30 to 87 hopefully the fan will run. This will prove the relay is at fault or you have a problem with the otter switch or associated wiring, but you said

"When I shorted the two wires on the otter switch together although the fan refused to go the relay could be heard clicking."

So I think the wiring sounds OK.

Good luck let us know how you get on.

When I shorted the wires on the otter switch the fan fefused to go but I didn't mention the relay clicking as to far away to tell.
Hi Paul
I have just spent 2 hours of back breaking pain (I have lower back isues)and this is what I have done
I get no reading on number 30 so with 30 to 87 bridged I get nothing also with 86 to 87 I get nothing but as in my original post when I bridge 85 to 87 then the fan comes on.
I cut off the black connector thats in the centre of my photo and have used a new connector but still there is no feed getting down to the fan even with the fan over ride switch on.
I took both the headlamp relay and fan relay apart and altough a little mucky inside they both click when I put power to them, they look identical so even swapping them around still to fan.
The wires going to the otter switch are live when I switch the fan over ride on but when I bridge the wires going to the otter switch still no fan.
If i connect a live direct from the battery to the fan then it comes on but if i connect a wire to the live feed to the otter switch then connect to the fan i get nothing so whilst still connected i took a reading and i get zero volts but once i disconect this wire from the fan the voltage is there again so very confusing.
I have to go out now but when I return later i will see if any new ideas have surfaced.
Thanks Paul

Edited by swimmer27 on Sunday 22 January 13:23

[swimmer27]

v8s4me said:

When you connected the fan directly to the battery I assume you connected it via the fan side of the long black connector? Did you check by feeding power to the loom side of that connector? I’ve got these connectors on my heated seats and so I know they aren’t very good and definitely not waterproof. Also use your multi-meter to see if power is getting to the loom side part of the connector.

I have cut this connector out now and renewed all the connection but still no live feed is getting to the fan only a live to the otter switch.

[Oldred_V8S]

swimmer27 said:

Reply below

I get no reading on number 30 so with 30 to 87 bridged I get nothing - 30 is a fused supply, is it possible this is the root cause? or it could be a result of you shorting something whilst troubleshooting. You are checking it with the ignition on aren't you?

also with 86 to 87 I get nothing but as in my original post when I bridge 85 to 87 then the fan comes on. Ok this is good, it just means TVR have not wired the relay coil in the conventional fashion, normally the live goes to 86

I cut off the black connector thats in the centre of my photo and have used a new connector but still there is no feed getting down to the fan even with the fan over ride switch on. No there wouldn't be if the issue is the relay and/or fuse.

I took both the headlamp relay and fan relay apart and altough a little mucky inside they both click when I put power to them, they look identical so even swapping them around still to fan. Leave them swapped around for now, at least whilst fault finding.

The wires going to the otter switch are live when I switch the fan over ride on but when I bridge the wires going to the otter switch still no fan.
If i connect a live direct from the battery to the fan then it comes on but if i connect a wire to the live feed to the otter switch then connect to the fan i get nothing so whilst still connected i took a reading and i get zero volts but once i disconect this wire from the fan the voltage is there again so very confusing. The otter switch is in the return part of the circuit, it does not supply +12v (at least not in any of the diagrams I have seen) so I wouldn't go connecting a live supply to it. The fact you have used the over-ride switch, shows it is not the otter switch. I would concentrate on finding out why you have no supply at the socket into which pin 30 of the relay plugs.

[swimmer27]

[quote=Oldred_V8S]

I get no reading on number 30 so with 30 to 87 bridged I get nothing - 30 is a fused supply, is it possible this is the root cause? or it could be a result of you shorting something whilst troubleshooting. You are checking it with the ignition on aren't you?

Yes ignition is on, when you say fuse supply do you mean an additional in line fuse as the fuse in the main fuse box where the relays sit are all ok?

Edited by swimmer27 on Sunday 22 January 14:59

[Oldred_V8S]

swimmer27]ldred_V8S said:

I get no reading on number 30 so with 30 to 87 bridged I get nothing - 30 is a fused supply, is it possible this is the root cause? or it could be a result of you shorting something whilst troubleshooting. You are checking it with the ignition on aren't you?

Yes ignition is on, when you say fuse supply do you mean an additional in line fuse as the fuse in the main fuse box where the relays sit are all ok?

Edited by swimmer27 on Sunday 22 January 14:59

There should only be one fuse, but I would look at the wiring to it and from it to the relay socket.

With thanks to mep12345 for the wiring diagram; it is a lot clearer than the one in the bible.

[tvrgit]

As oldred said earlier, that diagram clearly shows that the otter switch is on the EARTH side of the rel;ay, not the supply.

The OP's earlier posys suggest a live feed to the otter switch - if that is what you mean, then THAT IS WRONG. That would result in a 12v supply to both sides of the relay activiation circuit one 12v supply coming in as it should, from the fuse box, the other coming in from the otter switch. There is therefore no voltage difference across the relay so it won't activate.

Worse, and potentially (forgive the pun) dangerous, is the possibility of introducing a "backfeed" through the relay, when the car is witched off. An overheated relay and possible burny burny wiring in an unattended car is never a good idea.

The otter switch should not have a live supply. One of the terminals should show a permanent earth. The other should be live (12v) WHEN THE FAN IS OFF (ie when the otter switch is cold and the earth is therefore broken) and then show "earth" when the otter switch gets got enough and activates and earths the circuit.

The fan over-ride switch should EITHER (a) simply bridge those two terminals via two wires (which is the method I chose)) OR (b) connect between the second of the two terminals above and earth. No live supply should be taken to the otter switch.

Having said all that, if you haven't changed the override fan woring recently, then I still think it's the relay, or the connectors in the fuse box itself.

Edited by tvrgit on Sunday 22 January 16:54

[swimmer27]

Thanks one and all, afteranother hour I sat down with the Steve Heath book and realised I had miss read the fuse/relay diagram although when I showed it to my Girlfriend she could see why I had chose the wrong fuse



The words Engine Fan are sitting under the 10 amp fuse but the fan fuse is the one below it 25 amp so once I pulled this out it was blown and each time I put a new one in there was a flash when the fuse blew. I then ran the fan again direct from the battery and left it going then I could hear a noise so stopped the fan and noticed the fan blades were hitting the cowling. Out of the three retaing bolts one was missing and one was loose and heavily rusted. I have now secured the cowling put a new fuse in and with the enging cold I flicked the fan over ride switch and all was ok.

Thank you all especially Paul and Mep12345; I feel a bit stupid re the diagram but it is drawn / labled badly plus I'm still on antidepressants and feel tired and find it hard to concentrate at times.

Edited by swimmer27 on Sunday 22 January 18:50

Whilst sorting my fan I noticed this mess. I see they are on ebay for £38 unless anyone knows a cheaper place

Edited by swimmer27 on Sunday 22 January 19:00

Edited by swimmer27 on Sunday 22 January 19:01