ABY Rad fan into 7A

[Error404]

TRying to run an ABY ran fan in my 7A.
I've got an ABY fan loom and resistor pack on the way to me.

As a temporary measure to ge the car running i tried bridging the two positive feeds to the existing rad fan together since the ABY fan only has two terminals. I've tried to test the fan etc to see if it works and keep blowing the 30A fans fuse at the fuse board. Now i guess thats because it draws a load more current than the 7A / 3B unit?

Then it dawned on me that the ABY fan set-up is designed to work with the afterrun pump as well as the two stage cooling speeds. So in my set-up, will it be able to just ignore the fact that there is not after-run temp sensor and just use the rad thermo switch to trigger the middle and high speeds?

I'm also hoping this is just plug and play in the 7A - any BTDT on a 3B?
I guessed there will be a big *** power feed from the fuse board, a fuse holder, relay and then the loom out to the engine bay with the resistor pack?

also a good opportunity to install a tidy override switch into the dash i guess

[johne]

Then it dawned on me that the ABY fan set-up is designed to work with the afterrun pump as well as the two stage cooling speeds. So in my set-up, will it be able to just ignore the fact that there is not after-run temp sensor and just use the rad thermo switch to trigger the middle and high speeds?

Yes, that's exactly what will happen. The wiring diagrams on S2central.net explain how it's wired up. You just won't be using terminal E1 on the resistor plate (N39), just terminals E2 and E3 to give you the middle speed. Of course there's no resistor for max speed. I'm not familiar with the non ABY radiator wiring but given that terminals E2 to E3 are the equivalent to the resistor inside the original fan motor on your car it occurs to me that you won't need the ABY loom, just connect E2 to the wire that would have been connected to the slow speed terminal on your old fan motor and connect terminal E3 direct to the ABY fan motor along with your original full speed wire. Fit a 60amp fuse and you're done.

If you fire up an ABY fan direct without any limiting resistor, i.e. max fan speed mode there's a hell of an inrush current which will certainly make the engine shudder if it's running due to the surge load on the alternator. On ABY the fan motor fuse is S42 rated 60 amps.

If you fit a dashboard switch make sure it just parallels the thermo switch at the bottom of the radiator as that way it won't be handling the current for the fan motor, just the trigger current to the relevant relay.

John

[Error404]

Thanks mate, looks definately easier to go with adding the resistor to the existing circuit.
I'm a little confused though, since i have the ABY series resistor in my hand and it has 4 terminals not 3 as per the wiring diagram (from what i can work out as i am useless with wiring schematics )
Also the wiring colours do not match?

[johne]

Give me a few minutes and I'll see if I can check with mine under the car.

John

[Error404]

[johne]

OK, so this is what I've got: unfortunately my unit only has 3 terminals on it and the wiring colours do match but all is not lost.

This is what I have. Part number 447 959 493B (made in the UK, must be about the only part on the car that was )

Terminal E1 has a 2.5mm red/green or blue wire
Terminal E2 has a 4.0mm red/white wire
Termianl E3 has a 4.0mm red/black wire

It's the E2 and E3 terminals you would want to use, E1 is for the very low speed after run relay.

However, all you want here is a resistance of around 0.25 to 0.5 ohms, often written has R25 or R50. Resistances this low are hard to measure using a normal digital multimeter but in your case I'd just take the resistor pack you've got and just try each of any pair of terminals in turn until you find the pair that give you the radiator fan speed you want. The resistor packs are almost indestructable and the worse that can happen is that some combinations of terminals will give you a full speed fan or more likely no fan speed at all and you just move on to the next two.

Happy to PM you a phone number if you want to talk to me, or post up a picture of the resistor pack you've got and I'll try and suggest which terminals to use.

John

[Error404]

Thanks John, much appreciated - I may well do that

Bit of a spanner in the works at this stage - I've not been given the right loom
I've been sent the blower fan loom not the rad fan loom!

[johne]

...........and if you've been sent a blower fan resistor pack as well that puny little thing wouldn't last one second on the end of the radiator fan

You don't need the loom as you can find a length of sturdy 2 core wire. Heavy duty loudspeaker wire would do since all you need is to connect the two wires at the fan motor to E2 & E3 and long enough to reach wherever you mount the resistor pack. On ABY cars its mounted under the washer bottle and horn in the nearside wing.

John

[Error404]

Nope i think you're right.
Well i'm now on the hunt for a resistor pack, looks like modding the existing set-up as per your suggestion is the bets way to go

cheers
Alex

[DeS]

Sorry for refreshing.
I'm preparing radiator fan upgrade for my S2 3B (soon RS2 setup). I already have 500W ABY fan with cowl, ABY blue fan resistor.

My problem is with wiring.
Originaly 3B fan is connected with 3 wires (brown, red/black and red/blue) and has its own 1 port resistor with green/black and white/red wires. ABY has 2 wire connection nad use 3 port resistor. Can anyone help with this harrnes issue? I would be greatful.

[re2500]

Alex, let me know if you need the ABY Rad fan loom as i have one complete with resistor pack in my garage. Ive got the fan aswell as i was going to sell as a complete kit but can split if its any help?

[re2500]

Have you managed to fit the rad fan into the car yet? As when i test fitted into my CQ i found that i had to modify the position of the rad as the larger diameter fan motor wouldnt tuck under the ABS pump. Just food for thought......

[Error404]

Yeah found that too, modded the ABS bracketry to suit, but in the end I just ran with my 7A fan as I couldn't get hold of a loom. I've dropped you a PM mate

[Ruffiano]

hmm interesting things, i have an aby style fan and shroud, i'll come back and check this out!

[DeS]

Ok Guys, one more question. Is ABY resistor plug and play to 3B? Does 3B chassis has mounting for ABY resistor? I have tried to mount it and I guess a there's collision with 3B air duct for radiator. Any help?

Maybe someone can make me a close picture?

Regards,
P.