Buzzing Fan Relay
Discussion
The alternator died on my car today, and I've replaced it with an exchange unit (£75 inc. vat, quite reasonable I thought).
As I was testing it on a run along the local dual carriage way, I noticed a buzzing sound coming from the passenger footwell. I had pulled down the footgaurd and pulled out the ECU to get access to the battery. The buzzing sound varies with the revs of the engine and is coming from the fan relay (top left).
Anyone noticed this before? I thought it may be the regulator unit on the new alternator causing it, but everything else seems to be working fine (including the radio). Any ideas would be welcome?
As I was testing it on a run along the local dual carriage way, I noticed a buzzing sound coming from the passenger footwell. I had pulled down the footgaurd and pulled out the ECU to get access to the battery. The buzzing sound varies with the revs of the engine and is coming from the fan relay (top left).
Anyone noticed this before? I thought it may be the regulator unit on the new alternator causing it, but everything else seems to be working fine (including the radio). Any ideas would be welcome?
Should've seen this one coming.....
Out for a drive today and the car overheated - fans not coming on at all.
Opened the bonnet and touched the otter switch leads together - nothing, so I suspect it's the relay.
Luckily for me, the previous owner had some strange wiring running from the fans. Traced it back to the battery so after a few 'car park' mods outside Tesco, I had the fans running on constant and made it home.
I guess the buzzing sound from the relay was it final death cry!
Out for a drive today and the car overheated - fans not coming on at all.
Opened the bonnet and touched the otter switch leads together - nothing, so I suspect it's the relay.
Luckily for me, the previous owner had some strange wiring running from the fans. Traced it back to the battery so after a few 'car park' mods outside Tesco, I had the fans running on constant and made it home.
I guess the buzzing sound from the relay was it final death cry!
hi jeboa,
are you sure that the fuse for the fans is ok ? had the same prob two days ago with new fans built in. they worked correctly for 2 weeks and then suddenly did nothin any more. the prob was the 20 Amp fuse. my mechanic (who built the fans in) changed it into a 30 amp fuse and we´re now awaiting the result (100 points for 30 amp fuse ;-) hopefully). just kidding, but please check if the previous owner has "improved" the cooling so much, that he has probably taken out the fuses and therefore the relays get killed. i would´nt wonder if it is the fact.
greetz
Jerko
are you sure that the fuse for the fans is ok ? had the same prob two days ago with new fans built in. they worked correctly for 2 weeks and then suddenly did nothin any more. the prob was the 20 Amp fuse. my mechanic (who built the fans in) changed it into a 30 amp fuse and we´re now awaiting the result (100 points for 30 amp fuse ;-) hopefully). just kidding, but please check if the previous owner has "improved" the cooling so much, that he has probably taken out the fuses and therefore the relays get killed. i would´nt wonder if it is the fact.
greetz
Jerko
Found the problem!
I had mistakenly wired the ground to the 'W' output from the alternator.
The ground runs to the thermostatic switch on the coolant resevoir.
I think from reading earlier posts that the W output is used for a tacho o/p on land rovers.
Consequently the relay contacts were buzzing in sync to the engine revs.
Unfortunately it has damaged one relay (I have two relays - one for each fan)
Will get a new relay to fix the problem this week.
I had mistakenly wired the ground to the 'W' output from the alternator.
The ground runs to the thermostatic switch on the coolant resevoir.
I think from reading earlier posts that the W output is used for a tacho o/p on land rovers.
Consequently the relay contacts were buzzing in sync to the engine revs.
Unfortunately it has damaged one relay (I have two relays - one for each fan)
Will get a new relay to fix the problem this week.
Thanks Brian and Penelope!
I found another reason - the standby current draining the battery after a couple of weeks without driving the car.
I had 130 mA idle current. Took out the fuses one by one until it dropped - to 10 mA!!!!!!!! The main beam system was the problem.
Took out the relay - a standard one - and replaced it by one with a diode in series with the coil. Idle current 10 mA.
Now the Griff can stand for weeks without draining the battery - though not tested yet because of the fine summer weather :-).
I found another reason - the standby current draining the battery after a couple of weeks without driving the car.
I had 130 mA idle current. Took out the fuses one by one until it dropped - to 10 mA!!!!!!!! The main beam system was the problem.
Took out the relay - a standard one - and replaced it by one with a diode in series with the coil. Idle current 10 mA.
Now the Griff can stand for weeks without draining the battery - though not tested yet because of the fine summer weather :-).
And thanks to jeboa:
The ground wire on my alternator was connected to the tacho output. Moved it to the ground terminal next to it and upppss - no buzzing relay and 1 Volt more on the fans (12 volt).
Now: no cooling problem at all, even on 28 deg days, on a standards 400 cooling system :-)
The ground wire on my alternator was connected to the tacho output. Moved it to the ground terminal next to it and upppss - no buzzing relay and 1 Volt more on the fans (12 volt).
Now: no cooling problem at all, even on 28 deg days, on a standards 400 cooling system :-)
kolling said:
Thanks Brian and Penelope!
I found another reason - the standby current draining the battery after a couple of weeks without driving the car.
I had 130 mA idle current. Took out the fuses one by one until it dropped - to 10 mA!!!!!!!! The main beam system was the problem.
Took out the relay - a standard one - and replaced it by one with a diode in series with the coil. Idle current 10 mA.
Now the Griff can stand for weeks without draining the battery - though not tested yet because of the fine summer weather :-).
Very good thenI found another reason - the standby current draining the battery after a couple of weeks without driving the car.
I had 130 mA idle current. Took out the fuses one by one until it dropped - to 10 mA!!!!!!!! The main beam system was the problem.
Took out the relay - a standard one - and replaced it by one with a diode in series with the coil. Idle current 10 mA.
Now the Griff can stand for weeks without draining the battery - though not tested yet because of the fine summer weather :-).
The 120 ma battery drain being cured by the fitting of a relay with diode in series with the relay coil is pointing to a faulty fusebox, faulty relay elsewhere in fusebox, faulty lights control unit if fitted, faulty lights switch or incorrect wiring
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