Fans not kicking on
Discussion
Do a quick search on here as there have been several threads. But quickly, are neither fans working?
If fuses/relays are fine, you could try -
1.Poking a long screw driver into fan blades (ignition off!!) to see if they spin. If not the problem could be fan motors.
2. Try changing the fan motor wiring over (2x push connectors, again just to double check something not 'crossed'
3. Most likely is water temp sensor. It is located toward the rear on OS of engine block - don't confuse with another sensor on the same side located toward the front. You need to remove top of air filter to get at it - clamps + two allen bolts + 2x small breather pipes front and rear. The sensor has a two pin connector (just like air sensor) and is brass. Simply unscrew and replace (ca. £12). Use some RTF silicon and/or ptfe tape to re-seal and DO NOT OVERTIGHTEN - the brasss is hollow.
None of these may help, but its cheap and easy DIY.
Cheers
If fuses/relays are fine, you could try -
1.Poking a long screw driver into fan blades (ignition off!!) to see if they spin. If not the problem could be fan motors.
2. Try changing the fan motor wiring over (2x push connectors, again just to double check something not 'crossed'
3. Most likely is water temp sensor. It is located toward the rear on OS of engine block - don't confuse with another sensor on the same side located toward the front. You need to remove top of air filter to get at it - clamps + two allen bolts + 2x small breather pipes front and rear. The sensor has a two pin connector (just like air sensor) and is brass. Simply unscrew and replace (ca. £12). Use some RTF silicon and/or ptfe tape to re-seal and DO NOT OVERTIGHTEN - the brasss is hollow.
None of these may help, but its cheap and easy DIY.
Cheers
Hi guys,
Thanks for the input. Things tried so far:
Unclipped the air box and removed the two Allen bolts. The top cover moved easily at the front but seems to be rather tightly fitted at the back. Did not want to force it so just put everything back together and left it for now.
Parked the car on a slope so that the nose was up. Filled the water up via the main reservoir at the front of the engine via the brass screw. Topped up the secondary reservoir (half way) and started the engine. At 70 degrees I slightly opened blue cap and some air escaped. At 80 degrees I did the same but only water came out. The engine temp came up to 92-93 and the fans kicked in, but only for a moment. No fan action after that up to 98 when I switched the engine off.
Will allow the system to cool down before slightly opening the brass screw and blue cap to allow any further air to escape.
Odd that the fans kicked in for a moment and then cut out. Any ideas as to what that symptom could indicate?
TIA
Thanks for the input. Things tried so far:
Unclipped the air box and removed the two Allen bolts. The top cover moved easily at the front but seems to be rather tightly fitted at the back. Did not want to force it so just put everything back together and left it for now.
Parked the car on a slope so that the nose was up. Filled the water up via the main reservoir at the front of the engine via the brass screw. Topped up the secondary reservoir (half way) and started the engine. At 70 degrees I slightly opened blue cap and some air escaped. At 80 degrees I did the same but only water came out. The engine temp came up to 92-93 and the fans kicked in, but only for a moment. No fan action after that up to 98 when I switched the engine off.
Will allow the system to cool down before slightly opening the brass screw and blue cap to allow any further air to escape.
Odd that the fans kicked in for a moment and then cut out. Any ideas as to what that symptom could indicate?
TIA
Cuchillo said:
Hi guys,
Thanks for the input. Things tried so far:
Unclipped the air box and removed the two Allen bolts. The top cover moved easily at the front but seems to be rather tightly fitted at the back.
Odd that the fans kicked in for a moment and then cut out. Any ideas as to what that symptom could indicate?
At least you know its not the fan motors/connections!Thanks for the input. Things tried so far:
Unclipped the air box and removed the two Allen bolts. The top cover moved easily at the front but seems to be rather tightly fitted at the back.
Odd that the fans kicked in for a moment and then cut out. Any ideas as to what that symptom could indicate?
As far as I remember theres noting else holding the rear of the air box on. You can pull it up and forward to undo the rear breather pipe. Is it just tight under the windsreen wiper mechanism? Once off there is a test to determine whether it is a sensor issue - as before, search on here. I THINK the procedure is start the engine and THEN pull off the terminal from the sensor. Both fans should come on as a safety precaution. Otherwise its start the engine with the terminal ALREADY unclipped. Either way, you can't do any damage if you're operating under 100 degs.
On last point, symptom might indicate nothing. When fans are working normally they will cut in/out for a few moments. Also they are supposed to come on at different temps - one at 94 degs and one at 98ish.
Whatever, don't worry. This will turn out to be one of those small tvr glitches, which, whilst annoying at the time, you can learn something from.
Best of luck
earlyriser said:
I THINK the procedure is start the engine and THEN pull off the terminal from the sensor. Both fans should come on as a safety precaution. Otherwise its start the engine with the terminal ALREADY unclipped. Either way, you can't do any damage if you're operating under 100 degs.
This means running the engine with unfiltered air, i.e. an open air box? Hi Guys,
Many thanks for all the input
Water has cooled down and I slightly opened the blue and brass caps ... No air escaped and the water level in the secondary reservoir has stayed constant. So not losing any water and it is as bleed as I can get it.
There are THREE clamps to the air box! ... Once I found the third one the air box came out very cleanly. Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
Anyway, disconnected the water temp sensor and started the engine up and the fans kicked in immediately. The display shouted that there is an EFI Fault Code of 4. It stayed on as long as the engine was running. (I switched off the engine as soon as I confirmed that the noise I was hearing was the fans ~ 10 seconds)
Konrad, I re-fitted the air box before starting up the engine, no point compounding any problems
Early, don’t worry ... I have not got to the hair pulling out stage (yet)
The most frustrating part of all of this was that the wife and I entered a charity treasure hunt over the weekend and we were the only ones in a TVR. The usual “you will never make it to the end” comments were made and of course this issue popped up halfway through the first day! 
Guess they all had a laugh over that. Mind you, we did recover the car back home and the next morning rejoined the rally in the wife’s Tuscan S, which worked faultlessly! ... So we started the rally in the TVR and ended it in a TVR ... Just not the same one!
Another oddity. I noticed there are two insulated wirers with front and read knock sensor written on them and they are not connected to anything! ... Should these not be connected somewhere?
I guess the next thing to check/change is the water temp sensor. Does anyone know what the part number is? I am a bit hesitant to just take the part to Halfords in the hope that they recognise it! ... Or do I need to get this ordered? ... If so, from whom?
TIA
Many thanks for all the input
Water has cooled down and I slightly opened the blue and brass caps ... No air escaped and the water level in the secondary reservoir has stayed constant. So not losing any water and it is as bleed as I can get it.
There are THREE clamps to the air box! ... Once I found the third one the air box came out very cleanly. Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
Anyway, disconnected the water temp sensor and started the engine up and the fans kicked in immediately. The display shouted that there is an EFI Fault Code of 4. It stayed on as long as the engine was running. (I switched off the engine as soon as I confirmed that the noise I was hearing was the fans ~ 10 seconds)
Konrad, I re-fitted the air box before starting up the engine, no point compounding any problems
Early, don’t worry ... I have not got to the hair pulling out stage (yet)
The most frustrating part of all of this was that the wife and I entered a charity treasure hunt over the weekend and we were the only ones in a TVR. The usual “you will never make it to the end” comments were made and of course this issue popped up halfway through the first day! Guess they all had a laugh over that. Mind you, we did recover the car back home and the next morning rejoined the rally in the wife’s Tuscan S, which worked faultlessly! ... So we started the rally in the TVR and ended it in a TVR ... Just not the same one! Another oddity. I noticed there are two insulated wirers with front and read knock sensor written on them and they are not connected to anything! ... Should these not be connected somewhere?
I guess the next thing to check/change is the water temp sensor. Does anyone know what the part number is? I am a bit hesitant to just take the part to Halfords in the hope that they recognise it! ... Or do I need to get this ordered? ... If so, from whom?
TIA
Cuchillo said:
Hi Guys,
Many thanks for all the input
Water has cooled down and I slightly opened the blue and brass caps ... No air escaped and the water level in the secondary reservoir has stayed constant. So not losing any water and it is as bleed as I can get it.
There are THREE clamps to the air box! ... Once I found the third one the air box came out very cleanly. Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
Anyway, disconnected the water temp sensor and started the engine up and the fans kicked in immediately. The display shouted that there is an EFI Fault Code of 4. It stayed on as long as the engine was running. (I switched off the engine as soon as I confirmed that the noise I was hearing was the fans ~ 10 seconds)
Konrad, I re-fitted the air box before starting up the engine, no point compounding any problems
Early, don’t worry ... I have not got to the hair pulling out stage (yet) The most frustrating part of all of this was that the wife and I entered a charity treasure hunt over the weekend and we were the only ones in a TVR. The usual “you will never make it to the end” comments were made and of course this issue popped up halfway through the first day! Guess they all had a laugh over that. Mind you, we did recover the car back home and the next morning rejoined the rally in the wife’s Tuscan S, which worked faultlessly! ... So we started the rally in the TVR and ended it in a TVR ... Just not the same one!
Another oddity. I noticed there are two insulated wirers with front and read knock sensor written on them and they are not connected to anything! ... Should these not be connected somewhere?
I guess the next thing to check/change is the water temp sensor. Does anyone know what the part number is? I am a bit hesitant to just take the part to Halfords in the hope that they recognise it! ... Or do I need to get this ordered? ... If so, from whom?
TIA
Don't worry about the EFI fault on start-up, it's just telling you the fan switch sensor isn't connected (which you will already know as you disconnected it). The only thing thayt may happen if you drive the car for any period of time, then switch it off for a short period of time eg filling up with petrol, is that you may have problems starting as it will over fuel. If this happens open the bonnet and disconnect all the leads to the fuel injectors, turn the engine over and when it dies reconnect all the injectors and she will fire up when you turn it over. This is from recent experience.Many thanks for all the input
Water has cooled down and I slightly opened the blue and brass caps ... No air escaped and the water level in the secondary reservoir has stayed constant. So not losing any water and it is as bleed as I can get it.
There are THREE clamps to the air box! ... Once I found the third one the air box came out very cleanly. Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
Anyway, disconnected the water temp sensor and started the engine up and the fans kicked in immediately. The display shouted that there is an EFI Fault Code of 4. It stayed on as long as the engine was running. (I switched off the engine as soon as I confirmed that the noise I was hearing was the fans ~ 10 seconds)
Konrad, I re-fitted the air box before starting up the engine, no point compounding any problems
Early, don’t worry ... I have not got to the hair pulling out stage (yet)
The most frustrating part of all of this was that the wife and I entered a charity treasure hunt over the weekend and we were the only ones in a TVR. The usual “you will never make it to the end” comments were made and of course this issue popped up halfway through the first day! Guess they all had a laugh over that. Mind you, we did recover the car back home and the next morning rejoined the rally in the wife’s Tuscan S, which worked faultlessly! ... So we started the rally in the TVR and ended it in a TVR ... Just not the same one! Another oddity. I noticed there are two insulated wirers with front and read knock sensor written on them and they are not connected to anything! ... Should these not be connected somewhere?
I guess the next thing to check/change is the water temp sensor. Does anyone know what the part number is? I am a bit hesitant to just take the part to Halfords in the hope that they recognise it! ... Or do I need to get this ordered? ... If so, from whom?
TIA
Good luck.
Cuchillo said:
Hi Guys,
Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
Oops, yes Interestingly there are THREE pipes connected to the air box. A large and a small bore at the front and a small bore at the rear.
I was forgetting the largeer diameter one. Mind you I've not seen the car for 7 weeks ...I doubt Halfords will cary the part but any tvr dealer/specialist should. Buy two, one for a spare. I used the second one immediately after snapping the first one - how I laughed
As I said, hollow brass but you learn from experienceEdited by earlyriser on Monday 10th September 22:55
Hi Cuchillo
Check both the 2 pins on the temperature sensor and the 2 connections on the plug for any signs of corrosion (dreaded green stuff, etc)
I had exactly the same fault on my Cerbera and fixed it by scraping the sensor and plug pins clean with a very fine jewellers screwdriver (a bit awkward) and spraying both then with WD40.
Works a treat now and a cheaper, easier fix that I first expected.
Good Luck
Simon.
Check both the 2 pins on the temperature sensor and the 2 connections on the plug for any signs of corrosion (dreaded green stuff, etc)
I had exactly the same fault on my Cerbera and fixed it by scraping the sensor and plug pins clean with a very fine jewellers screwdriver (a bit awkward) and spraying both then with WD40.
Works a treat now and a cheaper, easier fix that I first expected.
Good Luck
Simon.
Edited by SimonKD on Tuesday 11th September 08:39
Hi guys,
Thanks for all your help
It was the temp sensor that was not working. Also, the "boot" covering the connector had split and some one had smeared a dollop of grease around the split. Of course, water had managed to get into the split and the connector was sitting in a "damp patch" nicely protected by the grease!
Any how, the Temp Sensor has been replaced and the wiring/connector/boot cut and replaced as well. We used bullet connectors and heat shrink to try and kept it all covered. All seems well at the moment.
Took the car out for a dive for an hour and the temp never went above 95!
Came home grinning like an 
!
Will have to double check the work over the weekend to make sure that everything has settled down.
Thanks once again!
Thanks for all your help
It was the temp sensor that was not working. Also, the "boot" covering the connector had split and some one had smeared a dollop of grease around the split. Of course, water had managed to get into the split and the connector was sitting in a "damp patch" nicely protected by the grease!
Any how, the Temp Sensor has been replaced and the wiring/connector/boot cut and replaced as well. We used bullet connectors and heat shrink to try and kept it all covered. All seems well at the moment.
Took the car out for a dive for an hour and the temp never went above 95!
Came home grinning like an ! Will have to double check the work over the weekend to make sure that everything has settled down.
Thanks once again!
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