Discussion
Yesterday morning the cooling fan stopped whilst in traffic approaching A33/M4 junction. Not too much of a problem as when I got onto the M4 the temperature dropped to 80C and I avoided traffic jams on my way to and from Swindon.
I've just been checking things out.
The fan has an over-ride switch ... this is not activating the fan.
Applying power to the fan causes it to work ... so it's a power feed problem.
My relay 'box'
does not equate to any configuration in the 'bible', neither can I identify any relay that has wiring such as listed in the 'bible', neither can I identify any relay that is not functioning. All relays appear to get power on the appropriate C contact.
I'm stumped!
Oh, and BTW, there is no otter switch on the radiator and I can't identify where the temperature switch is.
The engine is a factory fitted 4.0 Hot-wire ... the plumbing is a lot simpler than in the 'bible' - top hose, bottom hose, 2 x hoses to heater matrix ... and that's it!
Suggestions as to where to look next will be gratefully appreciated. Suggestions as to which book to buy on the engine also gratefully received. I can lash up a switched feed to the fan and might end up totally rewiring it if I can't get anywhere with the existing wiring. PS - it's pre-wired for 2 fans (there's a spare socket) ... is that usual?
Lastly, how does everyone else keep the trim up under the passenger dash when the weight of the relay 'box' keeps pressing it down?
Streaky
I've just been checking things out.
The fan has an over-ride switch ... this is not activating the fan.
Applying power to the fan causes it to work ... so it's a power feed problem.
My relay 'box'
does not equate to any configuration in the 'bible', neither can I identify any relay that has wiring such as listed in the 'bible', neither can I identify any relay that is not functioning. All relays appear to get power on the appropriate C contact. I'm stumped!
Oh, and BTW, there is no otter switch on the radiator and I can't identify where the temperature switch is.
The engine is a factory fitted 4.0 Hot-wire ... the plumbing is a lot simpler than in the 'bible' - top hose, bottom hose, 2 x hoses to heater matrix ... and that's it!
Suggestions as to where to look next will be gratefully appreciated. Suggestions as to which book to buy on the engine also gratefully received. I can lash up a switched feed to the fan and might end up totally rewiring it if I can't get anywhere with the existing wiring. PS - it's pre-wired for 2 fans (there's a spare socket) ... is that usual?
Lastly, how does everyone else keep the trim up under the passenger dash when the weight of the relay 'box'
keeps pressing it down? Streaky
Oops, sorry, thought that indicating that the relays had power would have been interpreted as meaning that the fuses were OK. Yes, I pulled and checked all the fuses in my 3 X 7 fuse-box (another non-standard item). Oh, and I also checked the two fuses I found 'floating' under the dashboard alongside the relay 'box' - Streaky
- Streaky
griffman said:
had this happen on my wedge in the past. it turned out that the fan itself had actually seized up. try turning it manually if it doesnt move freely then its shagged.
Mine too latley. Still turned all be it a naff effort. Turned it by hand and you could hear the sand for bearings complaining.
Otter switch on mine is the top right hand tank looking at the front. Thats where my overide switch goes to.
The wiring on my 350 used to overheat. This would cause the relay contacts to burn out and the fuse (30amp) to melt. The fuse would look ok but a thin film of molten plastic would form over the legs of the fuse and prevented a connection.
These problems happened on and off for the 5 years I have had the car and few weeks back I decided enaough was a enough, went down the breakers and got 2 x 30 amp relays/holders (one for each fan), some very thick wire and rewired the whole thing from scratch. Total cost £4.
Danny
These problems happened on and off for the 5 years I have had the car and few weeks back I decided enaough was a enough, went down the breakers and got 2 x 30 amp relays/holders (one for each fan), some very thick wire and rewired the whole thing from scratch. Total cost £4.
Danny
Just to recap:
The fuses are all OK.
The relays are all OK.
The fan turns OK when power applied. Not noisy nor stiff.
The override switch does not operate the fan unless a separate feed is applied.
The fan wiring is in parallel. Applying power to either the existing plug (to the fan) or the other socket (unused fan) causes the fan to operate.
My diagnosis is a fault in the feed wiring, but I can't trace it.
I'll run a new feed tomorrow, through a relay.
There is NO otter switch. There are no electrical connections to the radiator at all, nor trace of missing connections (eg. spare Lucar connectors, male or female).
This car was used by the factory for several years, it is very 'non-standard' (eg. fuses, relays).
It's a mystery!
Streaky
The fuses are all OK.
The relays are all OK.
The fan turns OK when power applied. Not noisy nor stiff.
The override switch does not operate the fan unless a separate feed is applied.
The fan wiring is in parallel. Applying power to either the existing plug (to the fan) or the other socket (unused fan) causes the fan to operate.
My diagnosis is a fault in the feed wiring, but I can't trace it.
I'll run a new feed tomorrow, through a relay.
There is NO otter switch. There are no electrical connections to the radiator at all, nor trace of missing connections (eg. spare Lucar connectors, male or female).
This car was used by the factory for several years, it is very 'non-standard' (eg. fuses, relays).
It's a mystery!
Streaky
The fan does NOT run continuously - unless switched by the override.
There are no electrical connections to any part of the plumbing that I can see/feel (and I can see all the radiator and hoses (except the final streatch to the heater matrix ... and I doubt the sender is there). My guess is that it's on the engine somewhere ... but where? Hence my question about the best book to buy covering the engine.
Splitting the loom is fraught with danger. I'll run another feed.
Thanks to all.
Streaky
There are no electrical connections to any part of the plumbing that I can see/feel (and I can see all the radiator and hoses (except the final streatch to the heater matrix ... and I doubt the sender is there). My guess is that it's on the engine somewhere ... but where? Hence my question about the best book to buy covering the engine.
Splitting the loom is fraught with danger. I'll run another feed.
Thanks to all.
Streaky
HeyAndy said:
You've lost me guys. But guess what happened today? My fan has suddenly switched itself on constantly and I don't know how to turn it off even when cold.
Disconnect one leg of the otter switch to prove the switch? If it goes off its that if not its elsewhere?
Just a thought. My overide shorts it and turns the fan on.
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