Slimline fans -wiring

[1xshaunx1 27]

As far as I know there is no timer on the oe fan set up, the speeds are operated by the rad thermo switch. You can test this on the OE circuits by bridging the plug and the fans come on, unbridge and they go strait off. The delay will be in the switch as it goes off 5 degrees or so less to what temp it came on. 

[1xshaunx1 27]

You could put a 3 pin two way toggle switch to ground to the wires from the thermo switch to manually bring them on, on either speed and test if they were working as they should with the pump without popping the bonnet and bridging plugs

[ABV-VR6 12]

4 hours ago, 1xshaunx1 said:

As far as I know there is no timer on the oe fan set up, the speeds are operated by the rad thermo switch. You can test this on the OE circuits by bridging the plug and the fans come on, unbridge and they go strait off. The delay will be in the switch as it goes off 5 degrees or so less to what temp it came on. 

Maybe I'm wrong but my understanding of the pump is that regardless of the engine temperature the pump will:

1) Come on while starting the car and that can be done by wiring to the thermo switch positive. That is to improve the heater core efficiency on start-up. 

2) Come on at lower and high speeds fan run, easily done by wiring respectively to the low and high probes on thermo switch. That is to help moving the huge amount of coolant the Corrado contains, help flow with the smaller diameter coolant hose going to the heater core and also effectiveness. 

3) Come on every time the engine is shut off regardless of the temperature or if the fans are on or off and for a 10 minutes duration. This was done after the heater core recall, the FCM was updated from 506 to 3A0 and a built-in 10 minutes timer was added to the FCM to do the after-run part of the auxiliary pump. That is there solely to move hot coolant after the engine is turned off to prevent warping of the head. 

Point 3 is the only one that poses a tricky problem. Maybe that's enough to just wire it via fans coming on? Maybe it's better to have it run for 10 minutes? Maybe your solution and what you're saying that the 5 degrees difference in the cool down will provide the time for the after-run function and that's enough (which I agree) anyway, that's the debate! With my limited knowledge of car electrical, the only solution I see right now if I really want that full 10 minutes after run feature would be to trigger the aux pump via a timer relay set at 10 minutes. 

I found old threads from this forum pre-update that talk about this without solid conclusion. I looked on vortex, all threads finish by either you don't need this (let the car idle for 2 minutes after hard drives) or VW installed it for a very good reason otherwise they would have saved the part money. I'm going to dig up the old Corrado club Canada next to see if I can find more on this. 

Cheers 

 

 

[1xshaunx1 27]

I’m pretty sure mine doesn’t stay on when I shut the engine off. I know it doesn’t. I’ll turn the key sometimes when I pull up and you can here the pump come on when I turn the key ignition on, engine off. Is it a year thing mines a 92. 

[1xshaunx1 27]

Can’t see you are going to get a lot of warping if the water has been cooled enough not to bring speed one fans on or it’s just shut itself off be 90 c or less. The bloody thing is supposed to be at its happiest then

[ABV-VR6 12]

23 minutes ago, 1xshaunx1 said:

I’m pretty sure mine doesn’t stay on when I shut the engine off. I know it doesn’t. I’ll turn the key sometimes when I pull up and you can here the pump come on when I turn the key ignition on, engine off. Is it a year thing mines a 92. 

It may be a year thing? Yours have the older style in-line thermo switch right? I wonder if you have 8 pins going to the FCM or the newer 10 pins that came with the recall or are on 93 models and up? I'll get to the bottom of this. But one things if clearer now, if you don't have it, never had it, what's the point of having it then? That's makes me second think the necessity of it! 

[ABV-VR6 12]

24 minutes ago, 1xshaunx1 said:

 

24 minutes ago, 1xshaunx1 said:

Can’t see you are going to get a lot of warping if the water has been cooled enough not to bring speed one fans on or it’s just shut itself off be 90 c or less. The bloody thing is supposed to be at its happiest then

I totally agree with you, that reasoning makes total sense to me!

[ABV-VR6 12]

That's from Dennis on the CCC forum, I think that confirms the thought and explain why your early VR didn't have the after-run mode. Still looking for more info... 

[ABV-VR6 12]

And more, okay now it's confirmed for the difference between early and later VR6 but still no wiring found about it. That said, at this point I think that if it wired the way early VR6 were/are, I don't see why there would be an issue. That, plus your last comment kind of convinced me. 

Now, I'll be working on a final wiring diagram! Cheers 

[1xshaunx1 27]

Easiest way if you really want after ignition pump run is to put a capacitor in the pump circuit on the ignition live to the relay. This would then release 12v slowly until discharged giving you a delay of the pump being turned off no matter what when the ignition is turned off. You could mount this in the car to keep it dry and safe with a diode after it. It’s how emergency lights work when you the power goes off

[ABV-VR6 12]

9 hours ago, 1xshaunx1 said:

Easiest way if you really want after ignition pump run is to put a capacitor in the pump circuit on the ignition live to the relay. This would then release 12v slowly until discharged giving you a delay of the pump being turned off no matter what when the ignition is turned off. You could mount this in the car to keep it dry and safe with a diode after it. It’s how emergency lights work when you the power goes off

Good point, I never though of capacitor and I'll look into it later today as I don't know anything about them. 

But what about as simple as adding a timer relay to it? It's small, can be weather proof and would fit right in by the other 3 relays for the fans. 

They only make them in 5 pins. If power coming in instead of constant battery 12V feed was the thermo switch power which would be turned only upon ignition. So thermo to 30. Pole 30 feeds 87A while off and that could be our timer set to 5 or 10 minutes so when ignition off it runs for the set time. Then pole 87 is triggered when the relay is energized which would turn on the auxiliary pump upon start up and at all time which I think it's supposed to be. 85 to chassis ground. Then pole 86 is left alone? 

What do you think mate? Am I starting to understand or I'm completely lost ha haa. 

https://www.ebay.ca/itm/Time-Delay-Relay-12v-Automotive-Automatic-5s-10s-1min-5min-10min-Switch-Turn-Off-/313630767138?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0

[Stone0311 0]

 

 

 

 

Right, it all works! You were right about this, I was going way overboard with 6mm wire, which wouldn't have fitted in all the connectors. i guess the original fan motor ran a much higher current. When I looked the actual ratings I found 1mm wire would be sufficient for fan speed 1. Anyway, this is what the finished wiring looked like:

 

Which is to this wiring diagram:

Essentially the same as the one at the top of the page but I have updated the wire thicknesses. Also I couldn't find Red/Green wire in 4mm so just used Red.

I used this wire:

Thin Wall Cable (autoelectricsupplies.co.uk)

And these connectors to splice the wires:

108961-000 Raychem - Te Connectivity, Butt Splice, Yellow, DuraSeal Series | Farnell

Which are Duraseal Yellow crimp butt connectors with heatshrink. These are nice because the heatshrink material gives a good seal around the wires at the connection. You need yellow (10-12AWG) for all connections I found. The Blue connectors (14-16 AWG) is just too small, even for the 1 and 2mm wire join, which approximately makes 13 AWG. You have to double over the end of the 2.0mm wire where it is on its own, but this is no big issue.

The resistors I used are:

HSC100R47J | TE Connectivity HSC100 Series Aluminium Housed Solder Lug Wire Wound Panel Mount Resistor, 470mΩ ±5% 100W | RS Components (rs-online.com)

For the fan speed 1 circuit. This is a 0.47 Ohm resistor as I couldn't find a 0.4 Ohm. Makes little difference though. Don't know if this is the best brand, but it seemed to have a better temperature stability.

And:

HSA50R10J | TE Connectivity HSA50 Series Aluminium Housed Solder Lug Wire Wound Panel Mount Resistor, 100mΩ ±5% 50W | RS Components (rs-online.com)

For fan speed 2.

At the end the resistances were about 0.7 Ohm for fan speed 1, 0.2 Ohm for fan speed 2 and 0.1 Ohm for fan speed 3. Little bit higher accounting for the extra resistances for the other circuit components, and possibly rounding due to my multimeter only going to 1 decimal place accuracy, but within the right original range.

You can also get the female connectors for the Comex slimline fans here:

2 Pin Plug Connector for Comex Fans from Merlin Motorsport

For straight plug and play. These (and the spade connectors on the Passat plug) are open barrel types so you will need the correct crimper tool. To get the existing wires out of the Passat spade connectors is a pain but doable. For the 2 larger connectors (Speed 3 and Ground) I found it was possible to hammer a small screwdriver (jewellery/watch type) down the back of the wire to open it up. Make sure the spade is held securely in a vice to stop it bending, and use pliers to hold the neck of the connector as well. For the smaller two it should be possible to pull the wires out with a pair of pliers, starting with one or two threads in the middle of the bunch. With the wires out you can just about open the metal enough to get the new wire in. Because you are reusing these I would solder as well as re-crimping them. I re-crimped and the seemed to be holding OK, but soldered as well as a back up. 

I then knocked up a bracket to mount the resistors on. Here is the finished setup:

 

Not my best wrapping! Thought I had ran out of the usual tape, and used the slightly furry stuff which doesn't look as neat, and then found the plain roll again. The panel for the resistors tucks around the side of the rad between the battery in the void behind the headlights, as my original plan of mounting the panel straight out clashed with the battery. This is it in the car:

 

The big downside with this is that you can't get the battery out without removing the fans as the plug is in the way...  Unfortunately I had no time to prototype this so  I had to live with it for the time being. I think it theoretically should be possible to slide the whole shroud out in one go to get the battery out but it's a pain, and I will need to try and remedy this longer term. In hindsight I should have kept the panel coming out perpendicularly but flipped so that the resistors are mounted in the fan slipstream; I may try and do this, although will have to try and find another Passat plug!

Anyway, I tested the three fan speeds with the battery prior to fitting and the all come on fine, and at different speeds (no reason why they shouldn't!) Since being on the car they do come on alright, although I can't really tell if all 3 speeds have been used yet. Not sure what temp speeds 2 and 3 come on and it's a bit hard to tell over the engine noise. 

Don't know if it was worth the hassle and expense yet, but the fans seem a bit quieter and on the initial slow (20-30mph), albeit, short driving runs the temp seems to have stayed about 90-100 degrees.

 

 

 

Hi@oneohtwo,

How is your setup performing? I am at the point of installing a similar slim setup and was going to follow your good work

 

As an aside I'm looking for a manual override as mine is a G60, assume it would just be a relay bypassing the thermoswitch to terminal 3 'connector on loom'?

 

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[ABV-VR6 12]

I know you're asking me but I'll share what I ended up doing. I decided to keep the FCM because the after-run feature seems important to me. I wired my 2 Spal fans the way it was explained in this video. Works flawlessly and exactly like OEM. And very simple to do. 

https://m.youtube.com/watch?v=KeSiN2FNZoM

[oneohtwo 8]

On 10/16/2022 at 5:18 PM, Stone0311 said:

 

 

 

 

 

 

Hi@oneohtwo,

How is your setup performing? I am at the point of installing a similar slim setup and was going to follow your good work

 

As an aside I'm looking for a manual override as mine is a G60, assume it would just be a relay bypassing the thermoswitch to terminal 3 'connector on loom'?

 

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All still appears to be functioning well. No issues thus far, fans always come on and temps are kept in check. I drove to Stealth on that hottest day of the year in the middle of the heatwave and they just about kept the water temp below 110 when driving slowly. 

There are a couple of things I would do slightly differently if I were to repeat:

1) Find a neater way to mount the resistors and plug mounting. The resistors are tucked down the side between the battery and headlight, but it doesn't look the neatest. And where I have the plug housing I can't get the battery out without removing the fan housing, which means removing the front end. Not ideal. The Varta batteries are slightly oversized for the tray so may not be an issue with a normal sized battery.

2) I'd possibly wire speed 1 through a single bigger resistor just to neaten up the wiring. Not a big issue either way though.

I quite like this setup because it replicates the OEM exactly, and all 3 speeds work as per the original. Mounting the resistors is a bit of a pain though so it's not quite as simple as the Humble Mechanic setup that ABV posted, but with my car I would rather have both fans coming on for speed 1 on balance.

[Stone0311 0]

That's good, was keen to keep the OEM speeds on both fans; need to find room for the resistors also, battery is in the boot but it's getting super congested in the engine bay

Anyone done a manual override?

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[Stone0311 0]

I know you're asking me but I'll share what I ended up doing. I decided to keep the FCM because the after-run feature seems important to me. I wired my 2 Spal fans the way it was explained in this video. Works flawlessly and exactly like OEM. And very simple to do. 

I'll have a watch, I've got no FCM like a VR6 - at least I hope I'm not missing one lol

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[oneohtwo 8]

Ohh yes, sorry I missed you said G60. I don't know if the OEM fan motor is the same for the G60 as the VR, but it has a smaller radiator doesn't it, so I am guessing it is different? In which case the resistors I have used might not be appropriate. Not sure how it would work without the FCM as well.

Likewise unsure about the manual override. Sorry, not the most helpful post, I am not too familiar with the G60 I'm afraid!

[1xshaunx1 27]

I have a manual override. I’m running similar to ABV post. Switch is to have both on full power. But I’ve got relays on mine so a live switch to the relays with a diode on. 

[Stone0311 0]

Ohh yes, sorry I missed you said G60. I don't know if the OEM fan motor is the same for the G60 as the VR, but it has a smaller radiator doesn't it, so I am guessing it is different? In which case the resistors I have used might not be appropriate. Not sure how it would work without the FCM as well. Likewise unsure about the manual override. Sorry, not the most helpful post, I am not too familiar with the G60 I'm afraid!

 

There's no difference noted between models for the fan part number on early models (all are 1 959 455k), later models don't differentiate either but show part number 1 959 455ak - not sure what or how significant the difference is?FCM I assume we're talking as per the attached?

G60 Wiring (attached) shows an after-run control unit which is relay 15

 

 

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[1xshaunx1 27]

If you are running with the standard set up with FCM you just provide switched power/earth to the black plug wiring on the thermostat housing to bring the fans on full. 

[Stone0311 0]

If you are running with the standard set up with FCM you just provide switched power/earth to the black plug wiring on the thermostat housing to bring the fans on full. 

Hi @1xshaunx1, I'm running the standard G60 wiring but don't have an FCM

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[oneohtwo 8]

Yeah that looks like the FCM. 

The wiring diagram is a bit different for the VR. There's only 1 resistor in the fan motor there rather than two for the VR, so I don't think my setup would be quite right for it. Does it say what T1v and T1x are, I don't really recognise the symbols?

If you can work out the resistance of the resistor in the motor I would have thought it would be quite straightforward to connect up to replicate the OEM. Presumably there's a three pin connector on the back of the motor?

 

[Stone0311 0]

Yeah, 3 pin as pics attached
T1x and T1v are just wire connectors

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[Celeste2026 0]

Do you know what is the cfm on the oem setup?