https://www.youtube.com/watch?v=mltc1nzpDO0

Dotted line shows the current fan connection 2 right most relays are AC and the 2 leftmost I will fit.
What's your opinion?

Sorry, I didn't have time to look up schematics, but I have some points based on your diagram:

- the old fan connection looks correct. I'm not sure what's the reason behind diode - both switches on R4 are mechanical, there's no need for protection. So, R2 is not needed.

- the R1 relay is also not needed, the switch is capable to operate the fan directly.

Also, there seem to be too many fuses. The 30A at start should be sufficient, as long as you keep correct gauge throughout the whole circuit.

 

5 hours ago, Papez said:

the old fan connection looks correct. I'm not sure what's the reason behind diode

I'm not sure either backfeesing isn't an issue nor that diode is a flossy one. So yeah it's in the wiring when trying to measure continuity I measured a forward voltage of 530mv so I figured there was a diode in series. 

 

5 hours ago, Papez said:

So, R2 is not needed

To tell you the truth due to the high amperage I wanted to drive the fan indirectly using 40a relays instead of the thermoswitch 

Plus the existing 12v wiring going to its first contact is not sufficient for both speeds. 

5 hours ago, Papez said:

The 30A at start should be sufficient, as long as you keep correct gauge throughout the whole circuit.

Some of them are existing the others I will add. 

It all can be done with minimum interference of the original wiring 

4 hours ago, Thefeliciahacker said:

To tell you the truth due to the high amperage I wanted to drive the fan indirectly using 40a relays instead of the thermoswitch 

Plus the existing 12v wiring going to its first contact is not sufficient for both speeds. 

In case of R2, you'd be driving it indirectly through R4, if you kept the current wiring - iirc, it's same on the factory AC.

 

 

In case of R1 - yes, it is better for the thermoswitch, but not necessary consodering there's a resistor that limits in-rush current (non-ac cars drive the fan directly without the resistor). Ofcourse, if there's not sufficient wiring, it's better to add the relay.

6 hours ago, Papez said:

iirc, it's same on the factory AC.

Yes I saw that but it appears they drive the low speed directly. 

I will not use the current wiring. 

As I want to have complete control. 

I highly doubt they (importer) installed the ac to factory specs 

The only thing that makes it visible is the In line fuse box. Minimal intervention of the factory wiring. 

Just the two solder points for the fan wires. 

This photo shows the cable rou ting alongside the factory harness. 

Improved wiring diagram

Main power delivering wire is 4mm^2.
Internal power connection wires are 2.5mm^2

Internal triggering connection wires are 0.75mm^2

R2->High speed fan 4mm^2.

R1->Low speed fan 2.5mm^2.

1->R1 and 2->R2 0.75mm^2
You could get away by downsizing wires but I wouldnt recommend it...

Edited 30 December, 20223 yr by Thefeliciahacker

There we go! 

On 30/12/2022 at 16:31, Thefeliciahacker said:

Yes I saw that but it appears they drive the low speed directly. 

 

Both in case of 1.3, as it uses fan from non-ac 1.6. I can understand reason behind that, as neitherrelay and switch are 100% reliable (espwcially in the engine bay environment) and putting them in series increases chance of failure. 

 

7 hours ago, Thefeliciahacker said:

There we go! 

 

I don't think this is good place for unit with exposed contacts, I'd put it closer to the battery or get enclosed relay box. (ideally both)

Edited 31 December, 20223 yr by Papez

1 hour ago, Papez said:

I don't think this is good place for unit with exposed contacts, I'd put it closer to the battery or get enclosed relay box. (ideally both)

i will be making an enclosure + the undertray covers that area up i think

 

1 hour ago, Papez said:

Both in case of 1.3, as it uses fan from non-ac 1.6. I can understand reason behind that, as neitherrelay and switch are 100% reliable (espwcially in the engine bay environment) and putting them in series increases chance of failure. 

having seen to many thermoswitches fail due to high amperage I would much rather choose the thermoswitch to drive 150ma relays than 20A continuous fan

Edited 31 December, 20223 yr by Thefeliciahacker

26 minutes ago, Thefeliciahacker said:

i will be making an enclosure + the undertray covers that area up i think

 

Make sure it's completely sealed. Water get's everywhere regardless ofnundertray and only little is needed to corrode the contacts. I had to replace whole blower wiring because of that...

 

There are sealed relay/fuse boxes available, they might make the job easier

13 minutes ago, Papez said:

There are sealed relay/fuse boxes available, they might make the job easier

Belive it or not my friend I SEARCHED my entire city to find 4pin realays, its like they have a shortage of them!!!
So I honestly did my very best quality wise plus I did not want to drill any holes in the car body!

Location altered based on your suggestions

I like your dual speed fan controller circuit. Thanks for sharing.

 

I agree with others about the initial placement of the relay group though. That was too low. New place is better.

 

You can always use 5 pin relays instead of four pin relays too. Like this one:

These are very cheap and very common.

 

Also, instead of searching for a special relay box, you can use a common electronic project box. They are dirt cheap and easy to find.

I found one example box, which has a clear cover too. If you place the relays and fuses appropriately, you can check their conditions visually (relay leds, fuse condition etc.) after closing the box. For waterproofing, you can use red liquid sealant around the cables' box entrance and around the box cover before screwing it.

8 hours ago, R_Blue said:

You can always use 5 pin relays instead of four pin relays too. Like this one:

indeed!

 

8 hours ago, R_Blue said:

Also, instead of searching for a special relay box, you can use a common electronic project box. They are dirt cheap and easy to find.

I found one example box, which has a clear cover too. If you place the relays and fuses appropriately, you can check their conditions visually (relay leds, fuse condition etc.) after closing the box. For waterproofing, you can use red liquid sealant around the cables' box entrance and around the box cover before screwing it.

Yes that was my og idea but I wanted to keep it as oem looking as possible, anyhow, the new placment is much safer and the relays made by mahle, so I think I am going to have no issue!
Will see tomorrow about the door seals.
I may have the answer!!

Well we have an issue. 

The fan doesn't kick on. 

If I manually short the power delivery to the thermoswitch with either of my contacts the circuit works flawlessly. 

The thermoswitch used is mahle. 

It has 3 contacts one labeled +

The others 1,2 respectively. 

So I'm feeding 12v in the plus one. 

And connecting the output to the 1,2 for high and low speed. 

Yet the water reaches 100c and neither the slow or the fast speed is initiated 

The thermoswitch used is MAHLE TSW 31
95-84
102-91
I can't understand whats wrong, maybe it just too high of a temperature, or there is air in the system...
I have no clue at this point, every suggestion is welcome!

The coolant temperature may be 100 at the engine, but with ambient temperatures low at this time of year, will probably be a lot lower at the thermoswitch. An IR thermometer pointed at radiator fins close to the thermoswitch may give clues about whether this hypothesis is correct/not.

7 minutes ago, Breezy_Pete said:

The coolant temperature may be 100 at the engine, but with ambient temperatures low at this time of year, will probably be a lot lower at the thermoswitch. An IR thermometer pointed at radiator fins close to the thermoswitch may give clues about whether this hypothesis is correct/not.

Huh, but why does it keep climbing?
I do have a FLIR thermal imaging camera, we shall check!

Maybe the coolant flow is low for some reason?

11 minutes ago, Breezy_Pete said:

Maybe the coolant flow is low for some reason

yeah air entrapment is my first thought

14 hours ago, Thefeliciahacker said:

The thermoswitch used is MAHLE TSW 31
95-84
102-91
I can't understand whats wrong, maybe it just too high of a temperature, or there is air in the system...
I have no clue at this point, every suggestion is welcome!

 

Did you drive the car after filling up the coolant? there are ton of bubbles in the circuit and they might need more flow to get out. The chamber where the switch sits is one of the places where air pockets might stay for a while. When my head gasket leaked, non-functional radiator fan was one of the first symptoms I noticed.

 

Also, the temp reading on the head might be some 5-10° higher than switching temp, especially if the circuit is cold - that's due to placement of the switch at the coldest place of the circuit, compared to sensor at the hottest place in the circuit. I used 88° switch from Estelle and it went off at ~95°. 

Edited 9 January, 20233 yr by Papez