Fans

[TOV!E]

Hi just noticed that the n/s fan (the first one that should come on)is not working but the off side fan is, are there 2 fuses for these or is the n/s fan fked....
Ihave checked all the connections and they seem to be o.k....

Forgot to say its a tuscan s mk2 convert

[nawarne]

TOV!E said:

Hi just noticed that the n/s fan (the first one that should come on)is not working but the off side fan is, are there 2 fuses for these or is the n/s fan fked....
Ihave checked all the connections and they seem to be o.k....

Forgot to say its a tuscan s mk2 convert

On my Mk.1, you can get the fans running by pulling the water temp. sensor (on the block btwn 3&4 throttles)
when the engine is running.
Maybe if you did this and 'wiggled' the fan connectors the N/S might come on?

Also, IIRC, there is a relay for each fan? Might be worth swapping the known good one for the other side?

Nick

[The Surveyor]

Yes, there are two relays. Simple test is to swap over the spade connectors near the fans so the other one kicks in first, that'll tell you if the problem is with the switching, or the fan.

If it's the switching, swap over the relays and then see if this brings the first fan in at the right temperature. You'll find the relay references in the fuse panel drawing in the handbook and from memory, they are the yellow ones.....

Mine did this a while ago and was sorted with a replacement relay. I now carry a spare!

Paul

[TOV!E]

Many Many thanks i will give it a try.........

[Konrod]

I had this and it was the connectors at the fan end - all looked OK but weren't. Replaced both connectors (whilst I was there) and all OK.

[nawarne]

Konrod said:

I had this and it was the connectors at the fan end - all looked OK but weren't. Replaced both connectors (whilst I was there) and all OK.

They are the usual culprits. Last summer, I happened to notice that the main bonnet was also 'fretting' on the wire(s) to the O/S fan - so that the copper conductor was starting to be exposed. I obviously fixed that issue - but I guess, had it gone un-noticed, that fan would have stopped working. So, something to check...hence my wiggling comment earlier.
Nick

[TOV!E]

Right i have checked all the 30amp fuses (i am still waiting for my handbook from TVR, it has only been 6 years, so should be with me soon) anyway i have also disconnected the ECU Water Temp Sensor,under the airbox, and when this is unpluged the fans both come on, so my next question is has anybody got a drawing of the fuses and relays as i can only think it can be a relay.
Is there 2 fuses for the fans or only one??????????????????.

[Basil Brush]

If the fans come on when the temp sensor is disconnected then all the fuses, relays etc must be ok? What temp is the fan kicking in at and have you compared the dash temp reading to the ecu?

[TOV!E]

Hi Baz, the second fan OSF comes on at around 80 degrees

[The Surveyor]

This is the Mk 1 Tuscan fuse board and there won't too many differences. There are 2No. 30 Amp Engine Fan fuses, and 2No. Fan relays.



Paul

[NCE 61]

Relays & fuses must be ok if both fans are coming on with the temperature sensor disconnected. This would indicate a defective sensor or the electrical connection to the sensor, normally the fans come on at 92 & 96 DegC

[TOV!E]

Thanks Paul for the diagram, i have copied it for future reference, and thank you Nick for the advise, i will go a get a new sensor and see what happens...Gordon

[glow worm]

The convertible/curvy dash fuse board .

[TOV!E]

Thanks Keith, I will copy this also.
So my next question is why does the second fan come on and not the first, and if I buy a new ecu thermostat will that solve the problem, as it is not the fuses or relays?????

[TOV!E]

TOV!E said:

Thanks Keith, I will copy this also.
So my next question is why does the second fan come on and not the first, and if I buy a new ecu thermostat will that solve the problem, as it is not the fuses or relays?????

[glow worm]

Not sure Gordon.. I know the fans are controlled by the ECU parameter settings, so I can't see a temp sensor being the problem. Otherwise both fans would be affected... I am no expert..If I get the opportunity I will ask an expert .
I'm off to POWER in two weeks to get a bespoke fuel mapping and the fan temp parameters changed.

[Basil Brush]

If the second fan is coming on at 80 degrees then there's something wrong on the sensor/ecu side. Do you have the diag software? If so you can see what temp the ecu is reading from the sensor to compare against the dash, which uses a different sensor.

[dvs_dave]

Basil Brush said:

If the second fan is coming on at 80 degrees then there's something wrong on the sensor/ecu side. Do you have the diag software? If so you can see what temp the ecu is reading from the sensor to compare against the dash, which uses a different sensor.

+1. Check the ECU temp verses the dash temp

When the temp gets higher does the other fan come on also? If so then your fans are just connected the wrong way round so no big deal.

[TOV!E]

Hi, only one fan comes on "the second one " I can only get the first fan to work when the sensor is unplugged from the engine......That's what I don't understand, why the first fan does not come on at all unless it is unplugged, I will fit a new sensor if that does not solve I will take it up to Dom.........

[glow worm]

I think there is a decription of operation in the ECU management s/w help... If the ECU see no input from the sensor it will switch the fans on all the time ... So if your sensor went kaput and gave no voltage the fans would be permantently ON ... So you would not overheat and do damage. As stated previously the dashboard temp and the ECU temp sensors are different sensors, which makes for confusion over readings.
80 degrees dash temp seems very low and wrong, which indicates the cyl head sensor is giving the wrong temperature readings to the ECU ... I'll copy the relevant help file for you if I can find it.

Just found it.. (The is the Multiple Yellow Cerbera version s/w (not the single Blue Cerbera version) ...the latest to my knowledge used by TVR for all speed 6s)

WATER TEMP
Water temperature is measured by the sensor located in the cylinder head. If the ECU detects
a fault with this reading it will substitute a value of 95°C. The engine cooling fans are
controlled by this temperature reading, and are turned on at 92°C, off at 88°C.
Therefore under fault conditions the cooling fans will be turned on.

RAD FAN
This denotes if the ECU has turned on the radiator cooling fans. It does this when the water
temp input is above 92°C for Fan 1, 94°C for Fan 2, or if a fault is present in the water temp input.
ECU pins 6 & 41 are grounded, to turn on the cooling fan relay(s). If the fans appear turned
on by the ECU but do not work, check, on a Cerbera, that:
the fan relay 1 & 7 has a 12V supply to pins 85 & 30/51, if it does not, check fuse 1 , 3 and
20.

WATER FLT
This fault is shown if the water temperature signal is out of range. If it occurs, a water temp of
95 C will be substituted, the cooling fans will be turned on to prevent overheating, and the
MIL lamp will be turned on.
Water fault can
be caused by: Water ingress into the water temperature sensor’s connector
or wiring
Mechanical damage to sensor or wiring
Corrosion on sensor terminals or connector
Faulty sensor

Edited by glow worm on Sunday 4th March 08:27