Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[jereboam]

Just been out to collect the wife.  When I stopped the car, I noticed that the cooling fan was still running, which surprised me, as I'd only driven 3 miles.  It was still running five minutes later.  When I got home, after another 3 miles, it was still going, and I couldn't find any way of making it stop. 

When I looked under the bonnet, I noticed that there was a lot of condensation on some of the metal pipes, and although I couldn't see it clearly, I got the impression that it wasn't the main radiator fan that was running.  So perhaps it's not the cooling fan after all, but something in the airco that's still running. 

Nothing I fiddled with or thumped had any effect, so I had to disconnect the battery.

Any suggestions?

[Debs.]

This also happened to my Miggy recently; the fans ran at half-speed continuously until (in fear of flattening it) I gave in and disconnected the battery.......`next morning (and with a cold engine) I reconnected the battery to see what happened and all was normal again.
I imagined a stuck thermo-switch and/or fan-relays....it hasn`t happened since. :-/

[RobG]

Just been out to collect the wife.  When I stopped the car, I noticed that the cooling fan was still running, which surprised me, as I'd only driven 3 miles.  It was still running five minutes later.  When I got home, after another 3 miles, it was still going, and I couldn't find any way of making it stop. 

When I looked under the bonnet, I noticed that there was a lot of condensation on some of the metal pipes, and although I couldn't see it clearly, I got the impression that it wasn't the main radiator fan that was running.  So perhaps it's not the cooling fan after all, but something in the airco that's still running. 

Nothing I fiddled with or thumped had any effect, so I had to disconnect the battery.

Any suggestions?

Means your A/C is working correctly

[jereboam]

This also happened to my Miggy recently; the fans ran at half-speed continuously until (in fear of flattening it) I gave in and disconnected the battery.......`next morning (and with a cold engine) I reconnected the battery to see what happened and all was normal again.
I imagined a stuck thermo-switch and/or fan-relays....it hasn`t happened since. :-/

Well, I hope mine does the same thing, because I don't have any ideas about it!

[Abiton]

This also happened to my Miggy recently; the fans ran at half-speed continuously until (in fear of flattening it) I gave in and disconnected the battery.......`next morning (and with a cold engine) I reconnected the battery to see what happened and all was normal again.
I imagined a stuck thermo-switch and/or fan-relays....it hasn`t happened since. :-/

I think the relay(s) are the more likely culprit.  The thermoswitch(es) only carry the coil current for the relays, which is unlikely to get the (thermoswitch)contacts hot enough to weld together, even if they've become 'tired'. 

The relay contacts, on the other hand, are carrying the full fan start-up current and then operating current every time the fan's triggered, and the arc as they break again when the temperature comes down, so more likely to get grotty, overheat and then possibly weld together (maybe only temporarily, against the return spring pull).

[jereboam]

Well, it wasn't "better" this morning.

It seems to be one of the two fans in front of the aircon condenser, and removing fuse 28a from the relay box stops it. 

So, two series of questions:

(1) - what else does fuse 28a control? Is it safe to drive the car with it removed?

(2) - how does one change a relay if that's what the problem is?  I thought they were plug-in units, but when I try to lift them, they seem to be wired in, so clearly I'm lifting the socket as well.  Are they standard, or will I have to get then fom a Vauxhall dealer? Is there any way to check the relay with it in place?  It should be fairly simple to check with a meter to test for a closed circuit once it's out. 

Since this is part of the aircon, why isn't it controlled by the ignition?  Or are the fans there to supplement the main cooling fan when the condenser sits in front of the radiator and don't actually form part of the aircon system?

[Kevin Wood]

If it's only one of the pair of fans it's almost certainly a stuck relay.

I would hazard a guess at K26 or K28 (7 & 8 in the diagram here: http://www.omegaowners.com/forum/YaBB.pl?num=1176542235).

They do pull out of the bases. They can be quite tight though.

If you can free the base try prising the relay out with a flat screwdriver.

If you remove only the troublesome relay you'll still have  enough fan functionality to prevent it overheating, IMHO.

Just get another relay from someone breaking a car and you should be fine.

Kevin

[jereboam]

Thanks for that.  I'll have a go at pulling the relays, but I can't do it now, as it's raining, and I don't feel like mucking about with car electrics in the wet.

Some more questions:

 - Is it possible that both fans are switched by one relay with multiple reeds?  This might mean that it overheats if I remove the relay.

 - Presumably, a reasonably competent mechanic should be able to pull the relays with fingers alone.  Being old and feeble, I might not be able to do it.  Is it possible to use a mole grip or pliers, or does that mean instant destruction of the relay casing? 

- I doubt if I can get hold of a replacement relay from a breaker quickly enough - I use the car daily - are they purpose-built or general use, and can I get one from the local Auto-Parts store or will I have to go to Vauxhall?

[Kneepad]

No molegrips or pliers, you'll crush it. They are very tight. As said get under it with a flat blade screwdriver and prise it out.   

[Kevin Wood]

- Is it possible that both fans are switched by one relay with multiple reeds?  This might mean that it overheats if I remove the relay.

There is a complex arrangement which can run the two front fans in series or parallel (slow or fast) depending on coolant temperature, air con state and pressure in the air con refrigerant system. This involves 3 or 4 relays.

There is an almost separate setup that runs the rear radiator fan  based only on coolant temperature so that will provide adequate cooling assuming it works. The only common component looks to be the radiator switch.

So, if the problem is in the front fans, and you remove the offending relay, the rear fan will be fine.

- Presumably, a reasonably competent mechanic should be able to pull the relays with fingers alone.  Being old and feeble, I might not be able to do it.  Is it possible to use a mole grip or pliers, or does that mean instant destruction of the relay casing? 

It'll crack the casing. Better off to unclip the holder from the side of the relay box and prise out with a screwdriver.

Not sure how easy the relays are to get hold of, to be honest. I've never had to buy one but I assume they'll be readily available from dealers.

Kevin

[Pete Elite]

I've got the same problem on my Elite with the front passenger side fan constantly on as soon as you switch the ignition on.
 I've tried changing all the relevant relays(and yes they are awkward to get out)with no success so have for now just pulled the fuse in the box under the bonnet.
 If it's not the relays then what else could cause the problem?

  Thanks,
             Pete .

[Kevin Wood]

Probably the thermoswitch in the radiator in your case although there is a relay that is triggered by the air con to activate the fans. K87 rings a bell.

Bear in mind that the front fans should run all the time the air con is active. That won't be until the engine is started.

Kevin

[Pete Elite]

Hi Kevin, thanks for your reply.
 My fan comes on with the ignition with climate on or off .

    Pete .

[jereboam]

Aren't motor cars wonderful? 

The decision of my younger son to cart himself and his battered old Peugeot 205 off to Bristol for the weekend at the crack of dawn on Saturday forced me to attempt to find a temporary solution to the problem in order that I would be able to cart myself and my battered old wife off to the supermarket.   On reconnecting the battery (the car, not the wife), and replacing the extracted fuse, the auxiliary fan did not start up!

It seems that either:

 (1) - just breaking the circuit by removing the fuse released the relay

 (2) - the little bit of gentle encouragement (with a 10mm spanner) that I used on relay K8 proved effective

or

 (3) - I had a visit from the Relay Fairy

I'm inclined to favour explanation (3).

And, for the record, younger son was still pottering around at home when we got back from the supermarket at 10:30.

[PhilRich]

Aren't motor cars wonderful? 

The decision of my younger son to cart himself and his battered old Peugeot 205 off to Bristol for the weekend at the crack of dawn on Saturday forced me to attempt to find a temporary solution to the problem in order that I would be able to cart myself and my battered old wife off to the supermarket.   On reconnecting the battery (the car, not the wife), and replacing the extracted fuse, the auxiliary fan did not start up!

It seems that either:

 (1) - just breaking the circuit by removing the fuse released the relay

 (2) - the little bit of gentle encouragement (with a 10mm spanner) that I used on relay K8 proved effective

or

 (3) - I had a visit from the Relay Fairy

I'm inclined to favour explanation (3).

And, for the record, younger son was still pottering around at home when we got back from the supermarket at 10:30.

[/highlight]




Tsk Tsk! Ruddy typical!!
Glad the Relay Fairy came to your aid