Help needed to diagnose cooling fan issue (thread 2)
Discussion
Hi all,
Following on from this thread:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
and this comment (from RS MEXCICO - Thanks!)
Yes there was a single relay version and a twin relay version for the cooling systm,AS per TVR sometimes its not quite right the first time .There was also different size fans fitted aswell ie, shift more air .The block in your hand with the grey/brown/blue/yellow wires in the back is for the heater motor (is it a griff).First have you a water leak in the footwell,possible water in relay board.At the top left of the board there should be some foam blocking a hole up also could have a grommet in.Pull it out and there should be a connector block for the front loom.Short out fan switch and check if there is a 12v feed to the 2 large pink wires.if so the problem is at the front of the car if not its relay board down.Easy job a single bolt uunder it in your picture,then check for loose blocks ,again check for 12v feed on the large pink wires.ON some cars the fan circuit had burnt out in the board itself.
I have managed to get the fuse board out and think I have found the 2 large pink wires mentioned above. It is also obvious that there is no 2nd relay hidden behind the panel. Can you confirm that these are the 2 wires:
If so then can I test at the connector block using a voltmeter with the positive against the wire / block interface and the negative against the battery negative terminal?
Thanks,
Rob
Following on from this thread:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
and this comment (from RS MEXCICO - Thanks!)
Yes there was a single relay version and a twin relay version for the cooling systm,AS per TVR sometimes its not quite right the first time .There was also different size fans fitted aswell ie, shift more air .The block in your hand with the grey/brown/blue/yellow wires in the back is for the heater motor (is it a griff).First have you a water leak in the footwell,possible water in relay board.At the top left of the board there should be some foam blocking a hole up also could have a grommet in.Pull it out and there should be a connector block for the front loom.Short out fan switch and check if there is a 12v feed to the 2 large pink wires.if so the problem is at the front of the car if not its relay board down.Easy job a single bolt uunder it in your picture,then check for loose blocks ,again check for 12v feed on the large pink wires.ON some cars the fan circuit had burnt out in the board itself.
I have managed to get the fuse board out and think I have found the 2 large pink wires mentioned above. It is also obvious that there is no 2nd relay hidden behind the panel. Can you confirm that these are the 2 wires:
If so then can I test at the connector block using a voltmeter with the positive against the wire / block interface and the negative against the battery negative terminal?
Thanks,
Rob
OK, Update:
I have confirmed the following connector is for the fan:
I've tested by measuring voltage accross wires 1 + 2 against the negative of the battery. The results are as follows:
Ignition off
0V over 1 + 2
Ignition on
0V over 1 + 2
Ignition on and fan switch shorted
11.5V over 1, 0.5V over 2
I have tried swapping the fan relay with the horm relay (same relay type) but no difference. This would suggest a problem with the board? The board looks good with no water staining etc? How could this be? I would have though it hard for a path in the board to actually burn out?
If it is the board then I have would imagine changing it will be a horrible job!!
Any suggestions would be much appreciated.
Regards,
Rob
I have confirmed the following connector is for the fan:
I've tested by measuring voltage accross wires 1 + 2 against the negative of the battery. The results are as follows:
Ignition off
0V over 1 + 2
Ignition on
0V over 1 + 2
Ignition on and fan switch shorted
11.5V over 1, 0.5V over 2
I have tried swapping the fan relay with the horm relay (same relay type) but no difference. This would suggest a problem with the board? The board looks good with no water staining etc? How could this be? I would have though it hard for a path in the board to actually burn out?
If it is the board then I have would imagine changing it will be a horrible job!!
Any suggestions would be much appreciated.
Regards,
Rob
Can you see any corrosion on any of the connections for the pink wires at the board.
Voltage loss is caused by resistance which as you have considered could be on the board but I would think more likely at a connector.
Must say looks dry.
If the wires are soldered onto the board, you may consider a dry solder joint which could look OK but mybe the weak link.
Do you have a problem with your battery draining ? I am thinking that a short could also drag the volts down but I dont think that your battery would stay charged very long.
Good Luck.
Voltage loss is caused by resistance which as you have considered could be on the board but I would think more likely at a connector.
Must say looks dry.
If the wires are soldered onto the board, you may consider a dry solder joint which could look OK but mybe the weak link.
Do you have a problem with your battery draining ? I am thinking that a short could also drag the volts down but I dont think that your battery would stay charged very long.
Good Luck.
Thanks for the update.
There is no solder whatsoever. The pink wires are crimped into the connector and look good. Also, the terminals of the connector to board interface are very clean, likewise the connectors on the relay.
Battery will last about 2-3 weeks without car being used.
Why would pink wire 2 not just be on the same terminal as pink wire 1?
Thanks,
Rob
There is no solder whatsoever. The pink wires are crimped into the connector and look good. Also, the terminals of the connector to board interface are very clean, likewise the connectors on the relay.
Battery will last about 2-3 weeks without car being used.
Why would pink wire 2 not just be on the same terminal as pink wire 1?
Thanks,
Rob
Edited by rjben on Friday 25th January 15:13
From your other thread, I guessed that the reason that the fans are supplied with two seperate wires through the relay is due to current load at the contact tips.
If the supply is lost after the relay and you bring the two wires together then you may double the load across the single contact and burn it out.
If the supply is lost after the relay and you bring the two wires together then you may double the load across the single contact and burn it out.
Edited by so called on Friday 25th January 17:31
so called said:
From your other thread, I guessed that the reason that the fans are supplied with two seperate wires through the relay is due to current load at the contact tips.
If the supply is lost after the relay and you bring the two wires together then you may double the load across the single contact and burn it out.
Yes, that was my concern. At the fan end the connector overloaded with both fans going through it. At the circuit board end I'm guessing that all the current goes through the same terminals on the relay (relay has 4 pins - does anybody know for sure?) - if this is the case then perhaps the circuit board connector can take the additional load? If the supply is lost after the relay and you bring the two wires together then you may double the load across the single contact and burn it out.
Edited by so called on Friday 25th January 17:31
Regards,
Rob
Did you check the earth connection down at the front chassis? If one fan is not working or turning slow it could be this bad earth. I had this, even directly connecting from the starter supply did not work. It's easy to check. Measure the resistance between the fan ground connector that is connected to the fan and the earth at the dyno or other good earth. Should be 0!
Peter
Peter
Much easier to have both fans coming on at half speed,(half current) and when full speed needed, take the supply from the starter motor supply. No need to do anything in the fuse box and halves the draw on the fuse box. Seeing your fan conectors though, you would need to go back to standard to make it plug and play.
Hi,
firstly don't believe the fuse panel diagram in the handbook. I found after mapping my fuse panel I had 2 fan relays with a fuse for each, not the 40 amp single relay set up as shown or expected.
Looking at your photos the brown connector with the thick pink wires is from block F on the fuse board. According to Spends excellent fuse board diagram your number 2 pink wire will be energised from pin 36 of relay number 8, which you do not have. I would have expected a relay here as you have the 2 air con relays in your footwell wiring loom (relay 8 is for air con option). Try a 4 pin relay in relay slot 8 (bottom row 2nd from the left) and energise the fan circuit and see what happens. If no luck try a relay in relay slot 7. My 94 air con griffith has fan relays in slot 1 and 7.
I would also check every fuse in the fuse panel and also replace the butchered fan connectors with a couple of water proof items.
Ozstyle.
firstly don't believe the fuse panel diagram in the handbook. I found after mapping my fuse panel I had 2 fan relays with a fuse for each, not the 40 amp single relay set up as shown or expected.
Looking at your photos the brown connector with the thick pink wires is from block F on the fuse board. According to Spends excellent fuse board diagram your number 2 pink wire will be energised from pin 36 of relay number 8, which you do not have. I would have expected a relay here as you have the 2 air con relays in your footwell wiring loom (relay 8 is for air con option). Try a 4 pin relay in relay slot 8 (bottom row 2nd from the left) and energise the fan circuit and see what happens. If no luck try a relay in relay slot 7. My 94 air con griffith has fan relays in slot 1 and 7.
I would also check every fuse in the fuse panel and also replace the butchered fan connectors with a couple of water proof items.
Ozstyle.
Ozstyle said:
Hi,
firstly don't believe the fuse panel diagram in the handbook. I found after mapping my fuse panel I had 2 fan relays with a fuse for each, not the 40 amp single relay set up as shown or expected.
Looking at your photos the brown connector with the thick pink wires is from block F on the fuse board. According to Spends excellent fuse board diagram your number 2 pink wire will be energised from pin 36 of relay number 8, which you do not have. I would have expected a relay here as you have the 2 air con relays in your footwell wiring loom (relay 8 is for air con option). Try a 4 pin relay in relay slot 8 (bottom row 2nd from the left) and energise the fan circuit and see what happens. If no luck try a relay in relay slot 7. My 94 air con griffith has fan relays in slot 1 and 7.
I would also check every fuse in the fuse panel and also replace the butchered fan connectors with a couple of water proof items.
Ozstyle.
You Sir have solved my cooling issue! A relay in slot 8 brought fan no2 to life!firstly don't believe the fuse panel diagram in the handbook. I found after mapping my fuse panel I had 2 fan relays with a fuse for each, not the 40 amp single relay set up as shown or expected.
Looking at your photos the brown connector with the thick pink wires is from block F on the fuse board. According to Spends excellent fuse board diagram your number 2 pink wire will be energised from pin 36 of relay number 8, which you do not have. I would have expected a relay here as you have the 2 air con relays in your footwell wiring loom (relay 8 is for air con option). Try a 4 pin relay in relay slot 8 (bottom row 2nd from the left) and energise the fan circuit and see what happens. If no luck try a relay in relay slot 7. My 94 air con griffith has fan relays in slot 1 and 7.
I would also check every fuse in the fuse panel and also replace the butchered fan connectors with a couple of water proof items.
Ozstyle.
My only slight worry now is why it had been removed and why the 2nd fan was wired in parallel to the 1st? I'll keep a nose out for burning smells from the footwell (lots of touching wood etc).
Thanks to all for your help,
Regards,
Rob
Glad it makes more sense upside down Oz
I am trying to produce a 'layered' drawing version which will be easier to follow, but QCad & OpenOffice aren't ideal.
Some cars seem to have the first relay switch on the second one (reduces shunting I guess - but a single point of failure), others have the otter switch ground both relays which accounts for which relay position you use (some of the relay sockets are hard wired to the fusebox bus - some are jumpered).
Sounds like someone butchered your car, because they couldn't be bothered to sort out how it worked when a relay/fuse failed. In fairness the handbook should have the correct layout??? I anally stick appendixes in mine whenever I make changes (I prob wouldn't remember otherwise ). hint hint make a note in the book & find out which fuse it is using whilst you are hot.
Id be more concerned about the missing blobs covering those copper fuse blocks causing smoke than your relays, put some silicone on them before you have an accident.
Dave
I am trying to produce a 'layered' drawing version which will be easier to follow, but QCad & OpenOffice aren't ideal.Some cars seem to have the first relay switch on the second one (reduces shunting I guess - but a single point of failure), others have the otter switch ground both relays which accounts for which relay position you use (some of the relay sockets are hard wired to the fusebox bus - some are jumpered).
Sounds like someone butchered your car, because they couldn't be bothered to sort out how it worked when a relay/fuse failed. In fairness the handbook should have the correct layout??? I anally stick appendixes in mine whenever I make changes (I prob wouldn't remember otherwise
). hint hint make a note in the book & find out which fuse it is using whilst you are hot.Id be more concerned about the missing blobs covering those copper fuse blocks causing smoke than your relays, put some silicone on them before you have an accident.
Dave
Thats good news.
You would be surprised at the novice style electrical fixes that you can come across. I have fixed at least 4 amatuer bodge jobs on my Griffith.
I mapped my fuse panel and found it was significantly different to the handbook, therefore several circuits had under rated and over rated fuses.
You would be surprised at the novice style electrical fixes that you can come across. I have fixed at least 4 amatuer bodge jobs on my Griffith.
I mapped my fuse panel and found it was significantly different to the handbook, therefore several circuits had under rated and over rated fuses.
A bit of history - On early Griff 500's both fans were wired together and ran through one 40 amp fuse. Problem was prolonged siitting in traffic caused this to blow and spres were not usually on the board. RAC didn't carry them either - hence one trip home on a truck for me in 1997. There were two ways around the problem - first use a 'Slow Blow' fuse - which just went later or second have the fans rewired to work independently through their own fuses so they would only pack up if the otter switch did. I guess quite a few cars were converted but I'm not sure there was ever a service bulletin on how to do it - guys working in the dealerships just came up with their own solution. ( and cars that were never driven in traffic possibly weren't modified)
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